Dept Ob Gyn Università Roma Tor Vergata Tel 39-06-85304150
giuseppe.rizzo@uniroma2.it
Giuseppe Rizzo specialist in Gynecology and Obstetrics from 1987. Present academic position is Professore aggregato in Obstetrics and Gynecology at the Università di Roma Tor Vergata. He is member of the medical staff of the Department of Obstetrics and Gynecology of the Ospedale Fatebenefratelli Isola Tiberina Roma His main fields of interest are prenatal diagnosis, fetal echocardiography, Doppler ultrasound, preterm delivery and 3D and 4D ultrasound.
Abstract: OBJECTIVE: The purpose of this study was to assess, in second-trimester fetuses with transposition of the great arteries (TGA), the performance of software (sonographically based volume computer-aided analysis) that automatically retrieves diagnostic cardiac planes from a 4-dimensional volume of the fetal chest obtained with spatiotemporal image correlation. METHODS: We retrospectively evaluated the 4-dimensional spatiotemporal image correlation volumes of 12 fetuses with TGA (complete TGA, 10 cases; correct TGA, 2 cases). The data were analyzed to determine whether the target diagnostic planes, that is, cardiac plane 1 (left ventricle outflow tract) and cardiac plane 2 (right ventricle outflow tract), were correctly identified in at least 1 of the 7 automatically generated tomographic sonographic image displays and whether they allowed diagnosis of TGA. RESULTS: In 9 of 10 fetuses with complete TGA, target diagnostic cardiac plane 1 showed a branching arterial vessel (pulmonary artery) arising from the left ventricle, whereas in 7 of 10 fetuses, the aorta arising from the right ventricle was shown. In both cases with correct TGA, the pulmonary artery starting from the morphologic left ventricle was shown, whereas in 1 of 2, the connection of the aorta with the morphologic right ventricle was found. In all of the fetuses with TGA, a ventricular arterial connection anomaly was shown in either cardiac plane 1 or 2. CONCLUSIONS: This automatic approach shows good retrieval of diagnostic cardiac planes in fetuses with TGA, which may improve diagnostic efficacy for this disease.
Abstract: OBJECTIVE: We sought to establish the effect of maternal smoking on placental volume and vascularization in early gestation. STUDY DESIGN: Three-dimensional power Doppler ultrasonography of the placenta was performed at 11+0 to 13+6 weeks in 80 pregnancies categorized according to cigarette consumption: group A never smoked, B smoking < 10 cigarettes/day, C smoking 10-20 cigarettes/day, and D smoking > 20 cigarettes/day. Using a standardized setting, placental volume and vascularization index (VI), flow index (FI), and vascularization flow index (VFI) were calculated. RESULTS: No differences were found in placental volume among groups. In groups C and D lower values were found for VI (group C: t = 4.52, P = .0002; group D: t = 3.72, P = .0014), FI (group C: t = 5.06, P = .0001; group D: t = 4.59, P = .0002), and VFI (group C: t = 3.49, P = .0024; group D: t = 2.88, P = .0095). Placental vascular indices were significantly related to birthweight (VI r = 0.563, FI r = 0.580, VFI r = 0.601; P < .001). CONCLUSIONS: Maternal smoking is associated with altered 3-dimensional placental Doppler indices and these changes are related to birth weight.
Abstract: OBJECTIVE: To compare the efficacy of uterine artery Doppler velocimetry and three-dimensional ultrasound placental volume calculation alone or in combination in predicting at 11-14 weeks of gestation those pregnancies who will develop pre-eclampsia. STUDY DESIGN: This was a prospective study of 348 nulliparous women scheduled for a routine prenatal ultrasound examination at 11-14 weeks. Color and pulsed wave Doppler was used to obtain uterine artery flow velocity waveforms transabdominally and the mean pulsatility index (PI) of the uterine arteries was calculated. The placental volume was measured by three-dimensional ultrasound using the virtual organ computer-aided analysis. Outcome variables considered were pre-eclampsia and pre-eclampsia requiring delivery <32 weeks. RESULTS: Pre-eclampsia developed in 4.1% of the patients studied and in 1.7% a delivery before 32 weeks was required. Placental volume resulted significantly lower in pregnancies who will develop pre-eclampsia (t=4.636, p<0.003) and this was particularly evident in those pregnancies delivering <32 weeks (t=9.704, p<0.0002). No relationship was found between placental volume and mean uterine artery PI (r=-0.08, p=0.327). Uterine artery PI and placental volume showed similar sensitivities in predicting pre-eclampsia (50% vs. 56%) and pre-eclampsia with delivery <32 weeks (66.7% vs. 66.7%). The combination of uterine artery PI and placental volume gave better results when compared to the single use of one of these parameters (pre-eclampsia sensitivity 68.7%, pre-eclampsia requiring delivery <32 weeks 83.3%). CONCLUSIONS: The combination of abnormal uterine artery Doppler and low placental volume at 11-14 weeks achieves better results than does either test alone in the prediction of pre-eclampsia.
Abstract: OBJECTIVE: The purpose of this study was to test the possibility of diagnosing ventricular septal defects (VSDs) by using tomographic ultrasound imaging (TUI) on 4-dimensional volumes of the fetal chest obtained with spatiotemporal image correlation and the color Doppler function. METHODS: We retrospectively evaluated the 4-dimensional spatiotemporal image correlation volumes of 8 fetuses with VSDs (single in 7 and double in 1) between 20 and 33 weeks' gestation. The data were analyzed to determine whether VSDs were correctly identified in at least 1 of 7 automatically generated TUI displays. RESULTS: All of the included VSDs were correctly identified with the use of an interslice distance in the TUI function ranging from 0.8 to 2 mm without the need to further manipulate the volume. CONCLUSIONS: This automatic approach shows good retrieval of diagnostic cardiac planes in fetuses with VSDs, which may improve the diagnostic accuracy for this disease.
Abstract: OBJECTIVE: To evaluate the incidence of abnormalities in velocity waveforms from ductus venosus (DV) and aortic isthmus (AoI) in fetuses with intrauterine growth restriction (IUGR) and their reciprocal temporal relationship. METHODS: DV and AoI velocity waveforms were recorded in 31 IUGR fetuses characterized either by absent end diastolic (20) or reverse flow (11) in umbilical artery. Abnormal velocity waveforms in DV and AoI were defined in presence of reverse diastolic flows. RESULTS: Abnormal DV velocity waveforms were present in 10 fetuses and were always associated with abnormalities. Abnormal AoI flows were also present in 10 fetuses of the remaining 21 fetuses with normal DV velocity waveforms (47.6%). Longitudinal monitoring of fetuses with normal DV flows showed a significantly shorter time interval in the onset of reverse flow in DV when abnormalities in AoI were present (4 vs 14 days p=0.001) irrespectively of gestational age or other potential confounding variables. CONCLUSIONS: Our data suggest that AoI velocity waveforms become abnormal at an earlier stage of fetal compromise than DV.
Abstract: OBJECTIVE: To prospectively analyze the accuracy and rapidity of four-dimensional (4D) ultrasonography with spatiotemporal image correlation (STIC) in the assessment of four-chamber view and outflow tracts in unselected fetuses and in fetuses with congenital heart defects (CHD) at 19-23 weeks of gestation. MATERIALS AND METHODS: 112 consecutive pregnancies undergoing routine second-trimester ultrasonographic scan and 10 pregnancies with fetuses with CHD affecting the great arteries formed the study group. From the four-chamber view, volumes of the fetal heart were acquired by the STIC technique and stored for a later offline analysis that was performed by two examiners blinded to the characteristics of the fetuses. Offline analysis was performed using a simplified multiplanar approach based on 3 different steps and one rotation finalized to visualize the four-chamber view and the left and right outflow tracts. RESULTS: Adequate recognition of four-chamber view and outflow tracts was obtained in more than 80% of the volumes. There were no false-positives and only one observer had a false-negative (interrupted aortic arch classified as normal). The mean time required to interpret 4D volumes was 3.7 min. CONCLUSIONS: The standard fetal cardiac anatomy survey can be performed in the second-trimester fetus by 4D STIC in both normal and abnormal hearts. This approach may reduce the operator's dependency in diagnosis of CHD.
Abstract: OBJECTIVE: Aortic isthmus (AoI) velocity waveforms are considered powerful indicators of hemodynamic deterioration in intrauterine growth-restricted (IUGR) fetuses. However, technical difficulties in sampling AoI velocity waveforms from the longitudinal aortic arch (LAA) have limited its clinical application thus far. In this study, we tested the possibility of recording AoI velocity waveforms from the 3-vessel (3V) view of the fetal mediastinum and comparing the agreement of these measurements with recordings from the LAA. METHODS: Doppler measurements of the pulsatility index (PI) from the AoI were performed in 70 fetuses (20 IUGR and 50 normally grown) between 20 and 34 weeks' gestation. All measurements were sampled in both the LAA and 3V views by the same investigator. Reliability was evaluated with intraclass correlation coefficients (ICCs), and Bland-Altman plots were generated. The time required to complete the measurements was compared. RESULTS: A high degree of reliability was observed between PI values obtained from LAA and 3V views in both IUGR and normally grown fetuses (all fetuses: ICC, 0.976; 95% confidence interval [CI], 0.961-0.985; normally grown: ICC, 0.839; 95% CI, 0.731-0.906; IUGR: ICC, 0.954; 95% CI, 0.886-0.982). However, recordings from the 3V view were significantly less time-consuming than those from the LLA view (mean +/- SD, 30.4 +/- 14.2 versus 52.8 +/- 29.4 seconds; P < .0001) and showed higher intraobserver reproducibility. CONCLUSIONS: In IUGR and normally grown fetuses, AoI waveforms can be reliably obtained from the 3V view with higher reproducibility and a shorter recording time.
Abstract: OBJECTIVE: A low combined cardiac output (CCO) to the placenta (placenta/CCO fraction) has been reported in growth-restricted (IUGR) fetuses, but the temporal sequence of these modifications in relation to other changes in the fetal circulation is unknown. The aim of this study was to evaluate the placenta/CCO fraction in relation to other hemodynamic changes in fetuses at risk of developing IUGR. METHODS: We studied 340 singleton nulliparous pregnancies characterized at 20-24 weeks by abnormal uterine artery pulsatility index (PI) values (> 95(th) centile). At this gestational age we measured fetal biometry and Doppler waveforms from the umbilical artery (UA), middle cerebral artery (MCA), ductus venosus (DV), umbilical vein (UV) and outflow tracts of both ventricles. The diameters of the semilunar valves and UV were measured and CCO (left cardiac + right cardiac outputs) and UV blood flow were calculated. The placenta/CCO fraction was calculated as UV flow as a percentage of CCO. RESULTS: There were 283 pregnancies with birth weight >or= 10(th) centile and normal UA-PI throughout gestation (Group A), 34 with birth weight < 10(th) centile and normal UA-PI throughout gestation (Group B) and 23 with birth weight < 10(th) centile and abnormal UA-PI developing later in gestation (Group C). At 20-24 weeks there were no differences among the three groups in fetal biometric parameters, PI values from the UA, MCA and DV, and CCO. UV flow and placenta/CCO fraction were significantly lower in Group C compared with Group A (UV flow delta value = - 1.439, P < 0.0001; placenta/CCO fraction delta value = - 1.74, P < 0.0001) but not in Group B. CONCLUSIONS: Our data suggest that, in fetuses developing IUGR secondary to placental compromise, UV flow and placental/CCO fraction are already reduced by 20-24 weeks, and that this reduction occurs earlier than do modifications in fetal size and arterial and venous PI values.
Abstract: OBJECTIVE: To establish the potential role of three-dimensional (3D) power Doppler evaluation of the placental circulation in aneuploidy screening at 11 to 13 + 6 weeks of gestation. METHODS: 3D power Doppler ultrasound examination of the placenta was performed in 25 pregnancies with fetuses with abnormal karyotype and in 100 control pregnancies at 11 to 13 + 6 weeks of gestation. Using the same pre-established settings for all cases, the vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were calculated for the whole placenta. RESULTS: In the chromosomally normal group all the vascular indices increased significantly with advancing gestation between 11 and 13 + 6 weeks (VI: r = 0.482, P < 0.001; FI: r = 0.295, P = 0.0029; VFI, r = 0.484, P < 0.001). In the chromosomally abnormal group, the flow indices were not significantly different from normal in cases with trisomy 21 (13 cases), but they were significantly reduced compared with normal in cases with trisomies 13 and 18 (VI: t = 8.321, P < 0.0001: FI: t = 12.934, P < 0.0001; VFI: t = 7.608, P < 0.0001). CONCLUSIONS: 3D power Doppler evaluation of the placental circulation is not useful in screening for trisomy 21, and unlikely to further increase the already high detection rate for trisomies 13 and 18. However, we provide normal ranges of placental vascular indices between 11 + 0 and 13 + 6 weeks of gestation, which may be useful in future research on placental vascularity in certain at-risk pregnancies.
Abstract: OBJECTIVE: To assess the agreement of stroke volume (SV) measured with two-dimensional (2D) ultrasonography with Doppler capability (vs) four-dimensional (4D) with spatiotemporal image correlation (STIC) in normal and growth restricted fetuses. METHODS: 2D Doppler and 4D STIC were used to measure SV of 40 normal fetuses at 20 to 22 and 28 to 32 weeks, and 16 growth-restricted fetuses at 26 to 34 weeks of gestation. Intraclass correlation was used to evaluate the agreement between left and right SV obtained by the two techniques, and proportionate Bland-Altman plots constructed. The time necessary to obtain SV was analyzed. RESULTS: The intraclass correlation coefficient between 2D Doppler and 4D STIC measurements for the left ventricle were 0.977 and 0.980 for the right ventricle. The proportionate limits of agreement between the two methods were 18.7 to 23.9% for the left ventricle and - 20.9 to 21.7% for the right ventricle. The time necessary to measure SV was significantly shorter with 4D STIC (3.1 (vs) 7.9 min p < 0.0001) than with 2D Doppler. CONCLUSIONS: There is a good agreement between SV measured either by 2D Doppler or by 4D STIC. The 4D STIC represents a simple and rapid technique to estimate fetal SV and promises to become the method of choice.
Abstract: OBJECTIVE: To evaluate cardiac function in structurally and chromosomally normal fetuses with increased nuchal translucency (NT). METHODS: Forty-two structurally and chromosomally normal fetuses with increased NT at 11-14 weeks of gestation underwent fetal echocardiographic examination at 20-23 weeks. Fifty fetuses with normal NT values were considered as controls. Pulmonary and aortic peak velocity and time to peak velocities were measured as indices of ventricular systolic function. The ratios between the E-wave and A-wave (E/A) and the ratios between the E-wave and time velocity integral (E/TVI) at the level of both atrioventricular valves were evaluated as indices of ventricular diastolic function. RESULTS: In fetuses with increased NT the E/A ratios were significantly decreased when compared to control fetuses at the level of both the mitral (0.52 +/- 0.09 vs. 0.60 +/- 0.10, P = 0.0002) and tricuspid (0.51 +/- 0.09 vs. 0.61 +/- 0.09, P < 0.0001) valves. Similar results were found for the E/TVI ratios (mitral valve 4.79 +/- 1.03 vs. 5.63 +/- 1.23, P = 0.0007 and tricuspid valve 4.40 +/- 0.88 vs. 5.19 +/- 0.82, P < 0.0001). No significant relationship was found between the degree of NT and the abnormalities in Doppler indices. There were no significant differences in Doppler systolic indices. CONCLUSION: Structurally and chromosomally normal fetuses with increased NT have low E/A and E/TVI ratios at 20-23 weeks of gestation. These findings might indicate cardiac diastolic dysfunction.
Abstract: Intrauterine growth retardation is a pathology which is found in 3-10% of all pregnancies and it is associated with around 20-25% of all fetal intrauterine deaths and with long-term neurologic sequelae. It presents an increased risk of distress during labor and delivery and a greater risk of perinatal mortality. The causes of IUGR and the cardiac and venous Doppler in normal fetuses are analyzed, and the hemodynamic cardiac modifications in IUGR fetus are discussed. The fetal cardiac function in intrauterine growth retardation shows a redistribution of the fetal cardiac output, which tends to favor the left ventricle as the mechanism to compensate for the uteroplacental insufficiency. The Doppler velocity indices are modified as the fetal condition progressively deteriorates and they represent an important tool for the management of the complicated pregnancy.
Abstract: OBJECTIVES: To measure fetal peripheral pulmonary artery velocity waveforms by Doppler ultrasonography in pregnancies complicated by premature rupture of membranes under 24 weeks' gestation and to relate the Doppler indices to the development of fetal pulmonary hypoplasia. DESIGN: A prospective longitudinal study of fetal peripheral pulmonary artery velocity waveforms from premature rupture of membranes to delivery. SUBJECTS: Twenty pregnancies complicated by premature rupture of membranes before 24 weeks of gestation and delivering after 26 weeks. METHODS: Peripheral pulmonary artery velocity waveforms were recorded by Doppler technique at weekly intervals until delivery and Pulsatility Index (PI) calculated. Pregnancies were managed conservatively according to an institutional management protocol. Pulmonary hypoplasia was defined at autopsy by lung/body weight ratios and radial alveolar counts. Pulsatility Indices of fetuses developing pulmonary hypoplasia were compared with those with a normal lung development. RESULTS: After premature rupture of membranes PI values were higher than normal reference limits for gestation, but no differences were found between the six fetuses which developed pulmonary hypoplasia and the remaining 14 fetuses with normal lung development. In this latter group PI values progressively decreased with advancing gestation (ANOVA for repeated measurements F = 11.61; P < or = 0.001), while they increased in fetuses developing pulmonary hypoplasia (F = 8.44; P < or = 0.001). As a consequence of these opposite trends significant differences in PI values were present between the two groups of fetuses from 2 weeks after the premature rupture of membranes. Two weeks after the premature rupture of membranes a PI value from the peripheral pulmonary arteries above the 95th centile had a sensitivity of 62.5%, specificity of 94.6%, positive predictive value of 83.3%, negative predictive value of 78.5% and relative risk of 3.88 (95th confidence interval 1.34-11.28) for the prediction of pulmonary hypoplasia. CONCLUSION: The measurement of peripheral pulmonary velocity waveforms may help to establish the risk of developing pulmonary hypoplasia in pregnancies complicated by premature rupture of membranes.
Abstract: OBJECTIVE: Interleukin-8 concentrations in cervical secretions have been related to microbial invasion of the amniotic cavity and histological chorioamnionitis. Since a short uterine cervix may be a risk factor for intrauterine infection, we set out to determine the interrelationship between cervical-secretion interleukin-8 concentration, cervical length measured by transvaginal sonography and intrauterine infection in women with preterm labor and intact membranes. DESIGN: The study group comprised 144 pregnant women admitted to hospital for preterm labor and intact membranes. At admission, interleukin-8 in cervical secretions was assayed. The uterine cervix was evaluated by transvaginal sonography and the cervical index (funnel length + 1)/cervical length) was measured. In all cases, amniotic fluid was obtained by amniocentesis immediately after cervical examination and was cultured for aerobic and anaerobic bacteria including Ureaplasma ureolyticum and Mycoplasma hominis. Placentas were analyzed at delivery for the presence of histological chorioamnionitis. RESULTS: Forty-three per cent (62/144) of pregnancies delivered preterm and 12.5% (18/144) of the amniotic fluid cultures were positive. Placentas were available from 54 pregnancies which delivered preterm and histological chorioamnionitis was found in 59.2% (32/54) of the cases. Interleukin-8 concentrations in cervical secretions were significantly higher in the presence of microbial invasion of the amniotic cavity (median 1191.5 ng/ml, range 812-5234 ng/ml vs. median 109 ng/ml, range 12-2231 ng/ml; p < or = 0.0001) and histological chorioamnionitis (median 982.5 ng/ml, range 430-5234 ng/ml vs. median 435 ng/ml, range 40-1750 ng/ml; p < or = 0.0001). Similarly, higher values for cervical index were obtained in the presence of a positive amniotic fluid culture (median 1.23, range 0.35-5.88 vs. median 0.29, range 0.024-4.85; p < or = 0.0001) or histological chorioamnionitis (median 1.18, range 0.043-5.88 vs. median 0.562, range 0.040-2.48; p = 0.011). Multiple logistic regression analysis indicates significant independent associations with a positive amniotic fluid culture and histological chorioamnionitis for the cervical interleukin-8 concentrations (amniotic fluid culture positive > or = 850, histological chorioamnionitis > or = 450) and for the cervical index (amniotic fluid culture positive < or = 0.58, histological chorioamnionitis < or = 0.56). CONCLUSIONS: Intrauterine infection is associated with increased interleukin-8 concentrations in cervical secretions and a short cervix. Their combined analysis may reduce the indications for invasive procedures and improve the selection of women in preterm labor who may benefit from antimicrobial treatment.
Abstract: > At present preterm delivery is the leading cause of perinatal morbidity and mortality and its incidence is remained stable during the past 10 years. Conventional methods of identifying patients at risk of preterm delivery such as obstetrics history, demographic factors or evaluation of uterine contractions and cervix by digital examination show disappointintly low sensitivity and positive predictive value. In this review we describe new ultrasonographic and biochemical approaches that have been recently proposed to screen for preterm labor both in patients with intact and with premature rupture of the membranes. The ultrasonographic detection of a short uterine cervix and/or of a dilation of the internal os, expression of weakening of the lower uterine segment or cervical ripening, seems to efficiently predict patients at risk of preterm delivery. The efficiency of this marker may be improved by the association with the assay of fetal fibronectin or pro inflammatory cytokines (interleukin-6 and interleukin-8) in cervical secretions. Further by the concentrations of interleukin-6 and interleukin-8 in cervical secretions seems to be possible to predict among patients in preterm labor those secondary to subclinical endoamniotic infection or chorioamnionitis. The use of these new markers in the future may allow a better identification of patients at risk of preterm labor and a proper selection of the treatment (medical or surgical) required for such patients.
Abstract: The objective of this study was to determine the value of interleukin-6 (IL-6) in cervical secretion to diagnose microbial invasion of the amniotic cavity in patients with premature rupture of the membranes. Cervical secretions were sampled immediately before amniocentesis in 124 patients with singleton pregnancies and preterm premature rupture of the membranes. Gestational age ranged between 24 and 32 weeks. Amniotic fluid was cultured and IL-6 measured in amniotic fluid and cervical secretions. A total of 33.8% (21/124) of the amniotic fluid cultures had positive results. In cervical secretions the median concentration of IL-6 was 672 pg/ml (range 5-1,250) in the presence of intra-amniotic infection in contrast to 95.5 pg/ml (range 12-640) in women with negative amniotic fluid culture (p </=0.001). There were no differences between IL-6 concentrations in the cervical secretions of patients with or without obvious leakage of amniotic fluid. A significant relationship was found between IL-6 levels in amniotic fluid and in cervical secretions (rho = 0.74, p </=0.001). An IL-6 level in cervical secretions >200 pg/ml had a sensitivity of 78.5%, a specificity of 73.1% and a relative risk of 4.6 for intra-amniotic infection. Receiver-operator characteristics curve analysis showed that IL-6 assay in cervical secretions is comparable to IL-6 assay in amniotic fluid in predicting intra-amniotic infection (p = 0.468). In conclusion, intra-amniotic infection is associated with increased levels of IL-6 and concentrations in cervical secretions are related to amniotic levels. The measurement of IL-6 in cervical secretions may help to noninvasively identify intra-amniotic infection among pregnancies with preterm premature rupture of membranes.
Abstract: The objective of this study was to compare the value of ultrasonographic assessment of the uterine cervix and amniotic fluid tests in the prediction of the interval from admission to delivery in patients with preterm premature rupture of membranes. Ninety-two patients admitted to the hospital for preterm premature rupture of membranes between 24 and 32 weeks of gestation underwent both transabdominal amniocentesis and transvaginal ultrasonographic evaluation of the uterine cervix. Amniotic fluid analyses included cultures for aerobic and anaerobic bacteria, mycoplasmas and ureaplasmas, white blood cell count and glucose and interleukin-6 determinations. The ultrasonographic variables evaluated were cervical length, presence of funneling and cervical index ((funnel length + 1)/cervical length). The outcome measure was the interval from admission to delivery. The median interval from admission to delivery was 4.5 days (range 0-36). An abnormal uterine cervix was associated with a short time interval (cervical length < or = 20 mm, median 2 days, range 0-14 vs. median 6 days, range 0-36; p < or = 0.0001; presence of funneling, median 3 days, range 1-31 vs. median 8 days, range 0-36; p < or = 0.001; cervical index > 0.50, median 2 days, range 0-7 vs. median 8 days, range 1-36; p < or = 0.0001). However, interleukin-6 concentration in the amniotic fluid was the best predictor of the interval from admission to delivery when compared to the ultrasonographic indices and to all the amniotic variables considered. Moreover, when a multiple model was applied, the cervical index significantly and independently improved the performance of interleukin-6 in the prediction of the interval from admission to delivery. These data suggest that the combined use of the amniotic fluid interleukin-6 assay and the cervical index in patients with preterm premature rupture of membranes provides a good prediction of the interval from admission to delivery, thus identifying a subgroup of patients at high risk of imminent delivery.
Abstract: OBJECTIVE: Percutaneous umbilical blood sampling induces a marked decrease of impedance to flow in the umbilical artery. Because these changes are believed to be the result of the release of prostanoids, we conducted a study to determine whether indomethacin administration before percutaneous umbilical blood sampling affects the hemodynamic response induced by this procedure. STUDY DESIGN: Percutaneous umbilical blood sampling was performed in 20 singleton pregnancies that were treated for 3 days before the procedure with indomethacin (25 mg orally 6 hours apart) as tocolytic agent and in 22 untreated pregnancies. All the procedures were uncomplicated, and sampling of the umbilical vein was confirmed by blood pressure measurement at the time of the procedure. The umbilical artery pulsatility index and the fetal heart rate were measured immediately before and after the procedure. The first and last aliquots of umbilical vein plasma obtained at the beginning and closing of the procedure were assayed for endothelin-1, 6-keto-prostaglandin F1 alpha and thromboxane B2. RESULTS: In untreated pregnancies percutaneous umbilical blood sampling induced a decrease of the umbilical artery pulsatility index (p < 0.0001) and an increase in 6-keto-prostaglandin F1 alpha (p < 0.001) and endothelin-1 levels (p = 0.001), whereas no significant changes were present in fetal heart rate and thromboxane B2 levels. In pregnancies treated with indomethacin, 6-keto-prostaglandin F1 alpha, and thromboxane B2, concentrations at the beginning of the procedure were both significantly less (p < 0.0001) than those found in untreated pregnancies. In pregnancies treated with indomethacin percutaneous umbilical blood sampling did not affect umbilical artery pulsatility index, and 6-keto-prostaglandin F1 alpha and thromboxane B2 levels did not vary during the procedure. However, endothelin-1 (p < 0.001) and fetal heart rate (p < 0.0001) increased after the procedure. CONCLUSION: Indomethacin affects the fetal hemodynamic response to percutaneous umbilical blood sampling by inhibiting the release of prostanoids and the fall in umbilical artery pulsatility index. Under this condition the fetus adapts to the procedure by increasing the heart rate.
Abstract: The objectives of this study were 1) to evaluate interleukin-8 concentrations in cervical secretions in predicting preterm delivery, microbial invasion of the amniotic cavity and histologic chorioamnionitis in patients with preterm labor and intact membranes and 2) to compare the diagnostic value of interleukin-8 with fetal fibronectin determinations in predicting preterm delivery, microbial invasion of the amniotic cavity and histologic chorioamnionitis in patients with preterm labor and intact membranes. Interleukin-8 and fetal fibronectin were assayed in cervical secretions in 106 patients with singleton pregnancies and intact membranes admitted for preterm labor. Amniotic fluid obtained by amniocentesis was cultured and placentas (No = 43) analyzed for the presence of chorioamnionitis. The prevalence of pregnancies delivered preterm was 46.2% (49/106) and 15.09% (16/106) of amniotic fluid cultures were positive. Interleukin-8 levels in cervical secretions were significantly increased in patients who delivered preterm (p < or = 0.0001), in presence of positive amniotic fluid culture (p = 0.0016) and histological chorioamnionitis (p = 0.008) than in patients with negative findings. Receiver-operator characteristics curve analysis showed that an interleukin-8 value > 450 pg/ml is comparable to that of a fetal fibronectin value > 50 ng/ml in predicting preterm delivery (p = 0.247). Among patients who delivered preterm interleukin-8 concentrations > 860 pg/ml predicted a positive amniotic fluid culture with a sensitivity of 81.2% and a specificity 66.6%. Further, in patients who delivered preterm and had a negative amniotic fluid culture, IL-8 concentrations > 480 pg/ml predicted histological chorioamnionitis with a sensitivity 78.5% and specificity 61.5%. A positive fetal fibronectin > 50 ng/ml was not predictve of either a positive amniotic fluid culture or the presence of histological chorioamnionitis. In conclusion, increased concentrations of interleukin-8 and fetal fibronectin are associated with impending delivery and their diagnostic value seems comparable. However, interleukin-8 concentrations identify patients at risk of a positive amniotic fluid culture and the presence of histological chorioamnionitis. Measurement of interleukin-8 in cervical secretion is a non-invasive method to identify patients at risk for both preterm delivery and intrauterine infection.
Abstract: OBJECTIVE: Our purpose was to relate velocity waveforms from the splenic artery with pH and blood gas levels measured at cordocentesis in small-for-gestational-age fetuses and to compare the diagnostic efficiency of splenic artery waveforms with that of other fetal arterial and venous vessels in predicting acid-base status. STUDY DESIGN: Cross-sectional recordings from the splenic artery were obtained by color and pulsed Doppler techniques in 316 appropriately grown fetuses, 12 small-for-gestational-age fetuses with normal umbilical artery velocity waveforms (group 1), and 30 small-for-gestational-age fetuses with abnormal umbilical artery velocity waveforms (group 2). Measurements of splenic artery pulsatility index values in small-for-gestational-age fetuses were compared with those of appropriate-for-gestational-age fetuses. Associations of splenic artery pulsatility index with Po2, Pco2, and pH values measured at cordocentesis were examined and compared with those of umbilical artery, middle cerebral artery, and inferior vena cava. RESULTS: In appropriately grown fetuses pulsatility index values from the splenic artery decrease with advancing gestation (r = 0.51, p < 0.0001). Splenic artery pulsatility index values are lower in group 2 (p < 0.001) but not in group 1 small-for-gestational-age fetuses (p = 0.211). The amplitude of the decrease in the pulsatility index is significantly associated with fetal hypoxemia (r = 0.646, p < 0.001), acidemia (r = 0.593, p < 0.001) and hypercapnia (r = 0.577, p < 0.001). However, logistic regression demonstrates that hypoxia is better predicted by middle cerebral artery pulsatility index, whereas hypercapnia and acidosis are more closely associated with the percent of reverse flow in inferior vena cava. CONCLUSION: A decrease in the splenic artery pulsatility index occurs in small-for-gestational-age fetuses in the presence of abnormal pH and blood gas values, but a more accurate assessment of acid-base status may be obtained with the study of the middle cerebral artery and inferior vena cava.
Abstract: OBJECTIVE: To determine whether blood levels of atrial natriuretic peptide in small for gestational age (SGA) fetuses are related to Doppler indices measured in arterial and venous vessels. METHODS: Atrial natriuretic peptide was assayed in fetal blood obtained at funipuncture in 42 third-trimester fetuses, of whom 11 were appropriate for gestational age (AGA) and 31 were SGA. Small for gestational age fetuses were divided into three groups according to Doppler findings in the umbilical artery and inferior vena cava: 1) normal in both vessels (n = 10); 2) abnormal in the umbilical artery but normal in the inferior vena cava (n = 10); and 3) abnormal in both vessels (n = 11). Atrial natriuretic peptide levels were related to Doppler indices and acid-base status of the fetal blood. RESULTS: Small for gestational age fetuses with abnormal waveforms in both vessels had higher atrial natriuretic peptide blood levels (median 544.8 pg/mL, range 404.2-1112.3) compared with AGA fetuses (median 316.8 pg/mL, range 159.3-470.1; P < or = .001), SGA fetuses with normal waveforms only in both vessels (median 299.8 pg/mL, range 242.6-480.5; P < or = .001), and SGA fetuses with abnormal waveforms only in the umbilical artery (median 367.6 pg/mL, range 192.7-748.9; P = .002). Blood levels of atrial natriuretic peptide were significantly related to the preload index in the inferior vena cava (p = 0.554, P < or = .001). This relation remained significant when the analysis was restricted to the SGA fetuses with abnormal waveforms in the umbilical artery and the inferior vena cava (p = 0.673, P = .03). CONCLUSIONS: Small for gestational age fetuses with abnormal velocity waveforms in the inferior vena cava have significantly higher concentrations of atrial natriuretic peptide. This may represent a compensatory mechanism in the SGA fetus for regulation of an abnormal hemodynamic condition.
Abstract: Flow velocity waveforms were recorded by Doppler ultrasonography from the uterine arteries, umbilical artery, thoracic descending aorta, renal artery and middle cerebral artery in fetuses of 57 pregnancies complicated by preterm labor with intact membranes. The uterine artery resistance index was significantly increased in patients with preterm labor when compared to reference limits for gestation, but no relationship was found with the time interval between Doppler recordings and delivery. The group of fetuses (n = 15) delivered within 48 h from entry to the study showed significantly reduced pulsatility index values from the middle cerebral artery when compared to fetuses delivered later or to the normal reference limits for gestation. No significant differences were found in the other vessels studied. In conclusion preterm delivery is associated with alterations in fetal cerebral waveforms and knowledge of these changes may prove useful in the evaluation of patients with preterm labor.
Abstract: Objective of this study was to establish the relationship in growth retarded fetuses between acid-base status in fetal blood obtained by cordocentesis and time interval between blood sampling and occurrence of antepartum heart rate late decelerations. Eighteen growth retarded fetuses scheduled for cordocentesis were considered for this study. All fetuses were free from structural and chromosomal abnormalities, characterized by absent end diastolic velocity waveforms in umbilical artery and later delivered for the development of antepartum heart rate late decelerations. Regression analysis showed that the time interval between cordocentesis and delivery was significantly related to pO2 (r = 0.46; p < or = 0.05) and pH (r = 0.57; p < or = 0.01) delta values but not with pCO2 values. Stepwise multiple regression analysis demonstrated that the severity of fetal acidosis significantly and independently predicted the length of this time interval even after controlling for confounding variables such as pO2 values, gestational age, presence of hypertension, or umbilical vein pulsations. The knowledge of this relationship may be useful in the clinical management of growth retarded fetuses.
Abstract: The objective of this study was to analyze the effects of cordocentesis on velocity waveforms recorded from the inferior vena cava and to evaluate differences, if any, in the hemodynamic response between normally grown and growth-retarded fetuses. Twenty-five normally grown fetuses and 20 growth-retarded fetuses were considered for this study. This latter group was characterized by abnormal Doppler indices in the umbilical artery and the middle cerebral artery suggestive of uteroplacental insufficiency as the causative factor of the impaired growth. Flow velocity waveforms were measured from the inferior vena cava immediately before and after cordocentesis and the % reverse flow during atrial contraction calculated. In normally grown fetuses the % reverse flow values did not vary significantly after cordocentesis, while in growth-retarded fetuses this index increased significantly after the procedure (p < or = 0.001). Furthermore, the amplitude of this increase was inversely related to pH levels in umbilical vein (p = 0.004). In conclusion, in growth-retarded fetuses cordocentesis induces an increase of % reverse flow in the inferior vena cava, while no modifications occur in normally grown fetuses. This suggests the presence in growth-retarded fetuses of an impaired cardiac adaptive mechanism to cordocentesis that may explain the higher incidence of complications occurring in such fetuses.
Abstract: The objective of this study was to evaluate the effect of fetal blood sampling on atrioventricular blood flow velocity waveforms. Flow velocity waveforms were measured from mitral and tricuspid valve immediately before and after fetal blood sampling in 25 normally grown and 10 growth-retarded fetuses. This latter group was characterized by abnormal Doppler indices in umbilical artery and middle cerebral artery suggestive of uteroplacental insufficiency as the causative factor of the impaired growth. The flow velocity parameters studied were peak velocity during early and active ventricular filling, time velocity integral, and fetal heart rate. Different indices were then calculated as expressions of ventricular diastolic function and cardiac output. In normally grown fetuses, both peak velocity during early diastole and time velocity integral values significantly increased after fetal blood sampling from both atrioventricular valves, whereas no significant changes were evidenced in the other parameters considered. Gestational age at the time of the procedure was positively related to the amplitude of these changes. In growth-retarded fetuses, fetal blood sampling induced a significant decrease in time velocity integral value form tricuspid valve, suggestive of a fall in right ventricle output. The amplitude of the decrease was significantly related to the severity of acidosis in umbilical vein. In conclusion, the cardiac hemodynamic response to fetal blood sampling differs between normally grown and growth-retarded fetuses. This difference may explain the higher rate of complications occurring in the latter group of fetuses after blood sampling.
Abstract: OBJECTIVE: The purpose of this study was to evaluate whether cordocentesis is associated with the release of vasoactive substances and whether there are differences between normally grown and growth-restricted fetuses. STUDY DESIGN: 6-Keto-prostaglandin F1 alpha (the stable metabolite of prostacyclin), endothelin-1, and cyclic guanosine monophosphate were measured in fetal blood at the beginning and closing of cordocentesis in 30 normally grown fetuses and 25 growth-restricted fetuses. This latter group was characterized by abnormal Doppler index values in umbilical artery and middle cerebral artery, suggestive of chronic hypoxemia as the causative factor of the impaired growth. In six growth-restricted fetuses bradycardia occurred at the end of the procedure. Umbilical artery pulsatility index was measured by Doppler ultrasonography immediately before and after the procedure. RESULTS: The median interval between the two blood samples obtained by cordocentesis was 90 seconds (range 60 to 320 seconds). During this interval a significant rise of 6-keto-prostaglandin F1 alpha (p < or = 0.0001) and endothelin-1 (p = 0.03) was evidenced in normally grown fetuses. The increase in 6-keto-prostaglandin F1 alpha was significantly related (r = 0.52, p = 0.002) to the fall of umbilical artery pulsatility index occurring after the procedure. In growth-restricted fetuses cordocentesis induced a marked increase of endothelin-1 (p = 0.0002), which was significantly related to the severity of acidosis (r = 0.52, p = 0.018), whereas no modifications were evidenced for the other agents tested. The increase of endothelin-1 was higher in those growth-restricted fetuses showing bradycardia at the end of the procedure than in growth-restricted fetuses that did not (p = 0.04). The variations of the vasoactive substances assayed were not significantly related to the type of procedure (transamniotic or transplacental), the amount of blood aspirated during the procedure, the interval elapsing between the first and second samples, the gestational age at which the procedure was performed, and the degree of fetal smallness. CONCLUSION: Cordocentesis induces the rapid release of vasoactive substances and the effect differs between normally grown and growth-restricted fetuses. This may explain the different hemodynamic response and the higher rate of complications occurring in the latter group after cordocentesis.
Abstract: OBJECTIVE: The objectives of this study were to determine whether cytokine levels in cervical secretions were increased in the presence of microbial invasion of the amniotic cavity in patients with preterm labor and intact membranes and to relate concentrations to cytokine levels in amniotic fluid, cervicovaginal microflora, and the presence of chorioamnionitis. STUDY DESIGN: Cervical secretions were sampled immediately before amniocentesis in 92 patients admitted for preterm labor with singleton pregnancies and intact membranes. Amniotic fluid was cultured and the following cytokines were measured in amniotic fluid and cervical secretions: interleukin-1 beta, interleukin-1 receptor antagonist, tumor necrosis factor-alpha, and interleukin-6. The cervicovaginal microflora and placentas (n = 42) were also analyzed. RESULTS: A total of 19.56% (18/92) of the amniotic fluid cultures had positive results. All the cytokines tested showed significantly higher levels in cervical secretions in the presence of intraamniotic infection. There were significant relationships between the concentrations of interleukin-6 and interleukin-1 receptor antagonist in amniotic fluid and cervical secretions. A concentration of interleukin-6 in cervical secretions > 410 pg/ml had a sensitivity of 66.8% and a specificity of 90.5% and a relative risk of 7.7 for intraamniotic infection, higher than the other cytokines tested. There were no relationships between the presence of bacterial vaginosis and cervicovaginal pathogens and cervical cytokine levels. In the presence of chorioamnionitis, cervical concentrations of interleukin-6 and interleukin-1 receptor antagonist were significantly increased in spite of negative amniotic fluid culture results. CONCLUSION: The measurement of interleukin-6 in cervical secretions may help to noninvasively identify intraamniotic infection among pregnancies with preterm labor and intact membranes.
Abstract: OBJECTIVE: We compared the diagnostic performances of fetal fibronectin assay of cervical and vaginal secretions and of transvaginal ultrasonographic evaluation of the uterine cervix in the prediction of preterm delivery of patients presenting with preterm labor and intact membranes. STUDY DESIGN: One hundred eight patients admitted to the hospital for preterm labor and with intact membranes underwent assay of fibronectin in the cervical and vaginal secretions and transvaginal ultrasonographic evaluation of the uterine cervix. The ultrasonographic parameters evaluated were cervical length, presence of funneling, and cervical index ([Funnel length + 1]/Cervical length). Outcome measures were occurrence of preterm delivery, defined as birth before the thirty-seventh week of gestation, and the admission-to-delivery interval. RESULTS: Forty-seven patients (43.5%) were delivered preterm. Receiver characteristic curve analysis showed that a level of fetal fibronectin in cervical secretions > or = 60 ng/ml had the highest diagnostic performance in predicting preterm delivery (sensitivity 80.9%, specificity 83.6%). Multiple stepwise logistic regression analysis indicated that the cervical index significantly improved the prediction of preterm delivery achieved by the fetal fibronectin assay. In patients with cervical secretion fibronectin levels > or = 60 ng/ml, survival analysis showed a shorter admission-to-delivery interval in the presence of an abnormal cervical index (p < or = 0.001). CONCLUSIONS: The assay of fetal fibronectin in cervical secretions is more accurate than ultrasonographic evaluation of the uterine cervix in the prediction of preterm delivery. Combined use of the fetal fibronectin assay and the cervical index improves the diagnostic efficiency and allows prediction of the admission-to-delivery interval, identifying a subgroup of patients who may require aggressive treatment.
Abstract: This study was performed to investigate whether fetal blood sampling and/or transplacental puncture are associated with changes of blood flow velocity waveforms in umbilical artery and fetal circulation. The pulsatility index (PI) was measured from umbilical artery, thoracic descending aorta, renal artery, and middle cerebral artery immediately before and after fetal blood sampling (n = 28) or third trimester amniocentesis (n = 32). No significant changes in PI values were evidenced after amniocentesis performed either transamniotically (n = 21) or transplacentally (n = 11). Fetal blood sampling induced a significant decrease of PI values in all the vessels investigated. However, in presence of a transplacental procedure (n = 15) the amplitude of the decrease of PI in umbilical artery was significantly higher than after a transamniotic procedure (n = 13), while no differences were evidenced in the other vessels tested. These findings indicate that umbilical cord puncture at the time of fetal blood sampling is associated with a decrease in PI in umbilical artery and several peripheral arterial vessels. The isolated placental puncture does not induce Doppler-detectable hemodynamic effects, while in conjunction with cord needling, it increases the amplitude of the effects in umbilical artery.
Abstract: The objective of this study was to describe blood flow velocity waveforms of fetal peripheral pulmonary arteries in normally grown and growth-retarded fetuses. Doppler studies were performed in 182 normally grown fetuses (gestational age 18-40 weeks) and in 61 growth-retarded fetuses (gestational age 24-36 weeks) that were free from structural and chromosomal abnormalities and whose umbilical and middle cerebral artery Doppler findings suggested uteroplacental insufficiency as the most likely etiology of the growth defect. The pulsatility index was used to quantify the velocity waveforms. Successful recordings were obtained in 90.1% of the normally grown and 93.4% of the growth-retarded fetuses. In normally grown fetuses the pulsatility index values significantly decreased with advancing gestation. In growth-retarded fetuses the pulsatility index values were significantly elevated compared to those of normal fetuses. A significant relationship was observed between the severity of hypoxia and pulsatility index values from the peripheral pulmonary arteries in 29 fetuses in which Doppler recordings were obtained immediately before cordocentesis. In conclusion, these data show that in normal fetuses the Doppler-measured impedance to flow in the peripheral pulmonary circulation decreases with advancing gestation. Impedance to flow in the lungs is elevated in the presence of growth retardation and this increase is related to the severity of fetal hypoxia.
Abstract: The objective of this study was to assess the value of Doppler indices calculated from the inferior vena cava and ductus venosus in the identification of acidemia and hypoxemia as determined by pH and gas analysis of fetal blood obtained by cordocentesis in growth-retarded fetuses. Doppler measurements were performed in the inferior vena cava and ductus venosus in 209 normally grown fetuses and in 89 growth-retarded fetuses. All growth-retarded fetuses were free from structural and chromosomal abnormalities, and uteroplacental insufficiency characterized by Doppler changes in the umbilical and middle cerebral arteries was the most likely etiology of the growth defect. In this group of fetuses, Doppler recordings were performed immediately before cordocentesis. Ten different indices were calculated from venous velocity waveforms, and reference limits for gestation were constructed by the cross-sectional analysis of data from normally grown fetuses. Logistic regression and receiver operator characteristic curve analysis were performed to examine the relationship between Doppler indices and acid-base status. The pre-load index (peak velocity during atrial contraction/peak velocity during systole) in the inferior vena cava was the best explanatory variable for acidemia (chi 2 = 48.33; p < or = 0.001). Hypoxemia was predicted less well by venous indices and the best results were achieved by the S/A ratio in the ductus venosus (chi 2 = 9.46; p < or = 0.005). In conclusion, our data suggest that acidosis in growth-retarded fetuses may be non-invasively identified by Doppler measurements of the inferior vena cava and that a higher efficiency can be achieved by the use of the pre-load index.
Abstract: The objective of this study was to examine the acid-base status in blood obtained at cordocentesis in growth-retarded fetuses with absent end-diastolic velocity in the umbilical artery and divided according to the presence or absence of pulsations in the umbilical vein. Twenty-six growth-retarded fetuses free from structural and chromosomal abnormalities were considered for this study. All the fetuses had absent end-diastolic velocity in the umbilical artery associated in 11 cases (42.3%) with pulsations in the umbilical vein. Gas analysis of fetal blood obtained by cordocentesis was performed immediately after the Doppler recordings. Hypoxemia, acidemia and hypercapnia were defined respectively as the presence of pH or pO2 values 2 standard deviations below the normal mean for gestation and of pCO2 values 2 standard deviations above the normal mean for gestation. Fetuses with umbilical vein pulsations had lower values of pH (p < or = 0.001) and pO2 (p < or = 0.05) and higher values of pCO2 (p < or = 0.001) when compared to those without pulsations. All fetuses with pulsations were hypoxemic and hypercapnic and the incidence of acidemia was 90.9%. Fetuses with continuous blood flow in the umbilical vein, although frequently hypoxemic (80%), have pCO2 and pH values within the normal range in 40 and 52.3% of the cases, respectively. In conclusion, in fetuses with absent end-diastolic velocity in the umbilical artery the presence of umbilical vein pulsations identifies a subgroup of fetuses with a more severe compromise of acid-base status. This may be useful in the selection of the timing of delivery of such fetuses.
Abstract: The objective of this study was to evaluate the effect of fetal blood sampling on ductus venosus hemodynamics. A secondary objective was to establish the relationship between the amplitude of these changes, if any, and different variables related either to the procedure of sampling or to fetal characteristics. The ratio was assessed between the systolic and atrial velocities from the ductus venosus that were measured immediately before and immediately after fetal blood sampling in 32 appropriately grown fetuses and in 12 growth-retarded fetuses. The latter group was characterized by abnormal Doppler indices in the umbilical artery and the middle cerebral artery, suggestive of uteroplacental insufficiency as the causative factor of the impaired growth. The systolic/atrial ratio fell significantly after fetal blood sampling, but this decrease was less evident in growth-retarded fetuses. Neither the site of needling (placental cord insertion or intrahepatic vein) nor transplacental puncture during the procedure affected this decline. Similarly, fetal smallness, the volume of fetal blood aspirated and baseline values in Doppler indices from the ductus venosus and middle cerebral artery were unrelated to the observed changes. Stepwise regression analysis indicated that the variables that most significantly and independently affect the decline of the Doppler index were gestational age at the time of the procedure and pO2 values in the umbilical vein. In conclusion, modifications in ductus hemodynamics are induced by fetal blood sampling. These changes are less evident in hypoxemic growth-retarded fetuses and this reduced hemodynamic response may explain the higher rate of complications occurring in such fetuses after blood sampling.
Abstract: A case of pyloric atresia diagnosed in the third trimester is described. Real-time ultrasonographic examination revealed polyhydramnios, enlarged stomach, evident gastric peristalsis and esophageal dilatation. Color and pulsed Doppler studies of the gastroesophageal junction revealed the presence of a biphasic flow pattern that was consistent with gastroesophageal reflux.
Abstract: The objective of this study was to establish the effect of thyrotropin releasing hormone on the fetal circulation of appropriately grown and growth-retarded fetuses. Doppler recordings were performed immediately before and 15 min after maternal administration of 400 micrograms of thyrotropin releasing hormone in 14 women with appropriately grown and 19 with growth-retarded fetuses. Furthermore, in six women with growth-retarded fetuses, serial recordings were performed at 2-hourly intervals for 8 h until a second thyrotropin releasing hormone dose was administered. Velocity waveforms were recorded from the outflow tracts, inferior vena cava, umbilical artery, middle cerebral artery and descending aorta, and different Doppler indices calculated. In appropriately grown fetuses, thyrotropin releasing hormone induced a significant increase of peak systolic velocity values in the aorta and pulmonary artery and an increase of Doppler-estimated cardiac output. In growth-retarded fetuses, these changes were more evident and associated with a significant decrease in reverse flow in the inferior vena cava during atrial contraction. No changes were observed in fetal heart rate or in the other fetal vessels investigated. In the growth-retarded fetuses followed longitudinally, these changes were evident for the following 8 h and were potentiated by the second thyrotropin releasing hormone administration. In conclusion, thyrotropin releasing hormone induces significant hemodynamic effects on the fetal heart that may temporarily improve the impaired cardiac function of growth-retarded fetuses.
Abstract: The objective of this study was to determine whether in growth-retarded fetuses secondary to uteroplacental insufficiency the cardiac ventricles exert a force different from that of appropriately grown fetuses. Doppler echocardiographic studies were performed in 156 appropriately grown fetuses (gestational age 18-38 weeks) and in 72 growth-retarded fetuses (gestational age 24-36 weeks) free from structural and chromosomal abnormalities and characterized by Doppler changes in the umbilical artery and middle cerebral artery suggesting uteroplacental insufficiency as the most likely etiology of the growth defect. Right and left ventricular ejection force values were calculated from velocity waveforms recorded at the level of aortic and pulmonary valves, according to Newton's second law of motion. In appropriately grown fetuses, left and right ventricular ejection force values significantly increased with advancing gestation and the two ventricles exerted similar force. In growth-retarded fetuses, the ventricular ejection force was significantly and symmetrically decreased in both ventricles. Among growth-retarded fetuses, a poorer perinatal outcome was observed in those fetuses in which the ejection force of both ventricles was below the 5th centile of the normal limits for gestation. In 12 growth-retarded fetuses followed longitudinally during the last week preceding intrauterine death or Cesarean section due to antepartum heart-rate late decelerations, a significant decrease of ejection force was found in both ventricles. Finally, a significant relationship was found between the severity of acidosis and right and left ventricular ejection force values in 22 fetuses in which Doppler recordings were performed immediately before cordocentesis.(ABSTRACT TRUNCATED AT 250 WORDS)
Abstract: The objective of this study was to investigate the effects in early gestation of retroplacental hematomas on Doppler indices measured in different fetal vascular districts and to relate these changes, if any, to the volume of hematoma and pregnancy outcome. Thirty-eight pregnancies complicated by bleeding and ultrasonographic findings of retroplacental hematomas were considered for this study. Menstrual age ranged between 9 and 14 weeks. Blood flow velocity waveforms were measured in the umbilical artery, descending aorta, middle cerebral artery, and inferior vena cava. The pulsatility index in arterial vessels was calculated as well as the percentage reverse flow in the inferior vena cava. The values obtained were compared to previously constructed reference limits. No significant differences were found for any of the Doppler indices when the values obtained in pregnancies complicated by retroplacental hematomas were compared to the reference limits. Furthermore no significant relationships were found between the Doppler indices and either the size of hematoma or pregnancy outcome. In conclusion, retroplacental hematoma does not induce hemodynamic effects in the fetal circulation before 14 weeks, menstrual age. These data do not support the use of Doppler ultrasonography in early gestation for pregnancies complicated by bleeding and retroplacental hematomas.
Abstract: The objective of this study was to evaluate the effect of fetal blood sampling on cardiac flow velocity waveforms. Flow velocity waveforms were measured from the ascending aorta and pulmonary artery immediately before and after fetal blood sampling in 29 normally grown and 12 growth-retarded fetuses. The latter group was characterized by abnormal Doppler indices in the umbilical artery and middle cerebral artery suggestive of uteroplacental insufficiency as the causative factor of the impaired growth. The flow velocity parameters studied were the peak velocity, the time to peak velocity, and the left and right cardiac output and their ratio. In normally grown fetuses, the peak velocity and right and left cardiac output values increased significantly after fetal blood sampling, while no significant changes were observed in the other indices considered. The gestational age at the time of the procedure was positively related to the amplitude of these changes. In growth-retarded fetuses, fetal blood sampling did not induce any significant increase in cardiac output or peak velocities, while in more than 50 per cent of the fetuses these Doppler indices decreased. The amplitude of the decrease was significantly related to the severity of acidosis in the umbilical vein. In conclusion, the cardiac haemodynamic response to fetal blood sampling differs between normally grown and growth-retarded fetuses. This difference may explain the higher rate of complications occurring in the latter group of fetuses after blood sampling.
Abstract: To assess the efficacy of the Doppler velocimetry of the uterine and umbilical arteries as a screening test for preeclampsia and fetal growth retardation, we studied 916 low risk pregnancies. The S/D ratios of the uterine and umbilical arteries were obtained at 19 to 24 weeks and at 26 to 31 weeks of gestational age. Mean values, receiver operator curves, and the diagnostic accuracy of the tests were calculated for the following end-points: (1) pregnancy-induced hypertension, (2) low birth weight for gestational age, (3) small for gestational age with abnormal outcome, (4) pregnancy-induced hypertension needing preterm delivery. The prevalences for these outcomes were 3.4%, 4.6%, 1%, and 0.7%, respectively. The study was blinded. The umbilical and uterine artery S/D ratios were significantly higher in the abnormal than in the normal outcome group. When uterine arteries were studied at 19 to 24 weeks, sensitivity was 59% in the detection of pregnancy-induced hypertension, 11% in the detection of small for gestational age fetuses, 33% in the detection of small for gestational age fetuses with abnormal outcome, and 83% in the detection of pregnancy induced hypertension needing preterm delivery; the corresponding values for specificity were 69%, 94%, 94%, and 68%. At 26 to 31 weeks the sensitivity values were respectively, 69%, 58%, 75%, and 100% and specificity values were 80%, 59%, 39%, and 79%. When umbilical arteries were studied at 19 to 24 weeks, sensitivity was 38% in the detection of pregnancy-induced hypertension, 46% in the detection of small for gestational age fetuses, 78% in the detection of small for gestational age fetuses with abnormal outcome, and 67% in the detection of pregnancy-induced hypertension needing preterm delivery. The corresponding values of specificity were 74% for all four groups. At 26 to 31 weeks the sensitivity values were 38%, 43%, 87%, and 67%, respectively, and specificity values were 80% for all four groups. We concluded that Doppler examinations of the uterine and umbilical arteries can detect, at midpregnancy, the severe forms of pregnancy-induced hypertension and small for gestational age fetuses but they cannot be used to screen a low risk population in which the prevalence of the disease is low, and hence the positive predictive value is low.
Abstract: The objectives of this study were (1) to detect vasoactive intestinal polypeptide in fetal blood obtained by cordocentesis (2) to examine possible changes in growth retarded fetuses and to establish relationships between its levels and fetal blood acid-base status as well as fetal haemodynamics as assessed by Doppler ultrasonography. Vasoactive intestinal polypeptide was measured in umbilical vein blood obtained at cordocentesis in 12 growth retarded fetuses and in 13 control fetuses. Umbilical vein pH and PO2 values were determined in all the cases. Before the procedure, Doppler indices were calculated from umbilical artery, middle cerebral artery, renal artery, cardiac outflow tracts and inferior vena cava. Simple and multiple stepwise regression analysis were performed to examine the relationships between Doppler indices, acid-base status and vasoactive intestinal polypeptide levels. In control fetuses, vasoactive intestinal polypeptide was always detectable in cord blood and its levels did not change with gestational age. In growth retarded fetuses, vasoactive intestinal polypeptide levels were higher and significantly related to umbilical vein PO2 levels, Pulsatility Index in umbilical artery, middle cerebral artery and renal artery, while no relationship was found with umbilical vein pH, cardiac and venous Doppler indices. Stepwise multiple regression demonstrated middle cerebral artery Pulsatility Index to be the best explanatory variable for vasoactive intestinal polypeptide levels. In conclusion, vasoactive intestinal polypeptide blood levels are increased in growth retarded fetuses and this increase is inversely related to the Doppler measured impedance to flow in middle cerebral artery.
Abstract: OBJECTIVE: To assess the value of Doppler indices, calculated from fetal arterial peripheral vessels, cardiac outflow tracts and venous vessels, in the identification of acidaemia, hypercapnia and hypoxaemia as determined by pH and gas analysis of fetal blood obtained by cordocentesis in growth retarded fetuses. DESIGN: Doppler measurements were taken from umbilical artery, thoracic descending aorta, renal artery, middle cerebral artery, cardiac outflow tracts, inferior vena cava and ductus venosus immediately before cordocentesis. Logistic regression and receiver-operator characteristic curve analysis were performed to examine the relation between Doppler indices and acid-base status. SETTING: Tertiary centre for fetal medicine. SUBJECTS: Forty-eight growth retarded fetuses fulfilling these criteria for inclusion: 1. absence of chromosomal and structural anomalies; 2. an abdominal circumference or ultrasonographic estimated fetal weight less than the 5th centile; 3. presence of abnormal velocity waveforms in umbilical artery; and 4. postnatal confirmation of a birthweight below the 5th centile and absence of structural anomalies. RESULTS: The percentage of reverse flow in inferior vena cava was a more closely related variable for acidaemia (chi 2 = 29.69; P < or = 0.001) and hypercapnia (chi 2 = 12.86; P < or = 0.001) than the other Doppler indices. Hypoxaemia was better predicted by the pulsatility index from middle cerebral artery (chi 2 = 15.31; P < or = 0.001). CONCLUSION: The analysis of velocity waveforms from inferior vena cava and middle cerebral artery can be used to predict acid-base status in growth retarded fetuses secondary to placental insufficiency. This may lead to a more accurate antepartum monitoring of such fetuses.
Abstract: OBJECTIVE: Our purpose was to determine whether in early gestation cardiac and venous blood flow patterns of fetuses of insulin-dependent diabetic mothers differ from those of normal fetuses. STUDY DESIGN: Serial recordings were obtained at 12, 16, and 20 weeks of gestation in 11 normal fetuses, 16 fetuses of insulin-dependent diabetic mothers with first-trimester glycosylated hemoglobin levels < or = 8.5% (group 1), and 11 fetuses of insulin-dependent diabetic mothers with first-trimester glycosylated hemoglobin levels > 8.5% (group 2). Velocity waveforms at the level of atrioventricular valves, inferior vena cava, and umbilical vein were recorded by means of color and pulsed Doppler equipment by either transvaginal or transabdominal approaches. The following variables were measured: ratio between the peak velocities during early passive ventricular filling and active atrial filling at the level of atrioventricular valves, percent reverse flow during atrial contraction in inferior vena cava, and pulsations in umbilical vein. RESULTS: In all the fetuses the ratios between early and active ventricular filling increased linearly with advancing gestation, whereas the percent reverse flow in the inferior vena cava decreased linearly. However, fetuses of diabetic mothers showed significant differences in the slope of the functions describing the development with gestation of these index values, resulting in lower values of the ratios between early and active ventricular filling at the level of both ventricular valves and higher values of percent reverse flow in inferior vena cava. These differences were more evident in group 2 fetuses of diabetic mothers, and statistically significant differences were found in the slope values compared with group 1 fetuses. In normal fetuses umbilical vein pulsations were present only in two fetuses at 12 weeks of gestation (18.18%) and were never evidenced later in gestation. A significantly higher incidence of pulsations was found at 12 weeks in fetuses of diabetic mothers (group 1, 56.25%; group 2, 81.81%) and pulsations were present until 16 weeks (group 1, 37.5%; group 2, 45.47%). CONCLUSIONS: An impaired development of cardiac and venous blood flow patterns occurs in fetuses in insulin-dependent diabetic mothers. These abnormalities are more evident in pregnancies with poorer glycemic control but still occur in the presence of stricter metabolic control.
Abstract: In an effort to determine the factors influencing the abnormal ventricular filling patterns of fetuses of type I diabetic mothers, Doppler flow velocity waveforms were recorded from fetal atrioventricular valves in 37 pregnancies complicated by type I diabetes immediately before an elective cesarean section. The ratio between the peak velocities during early passive ventricular filling and active atrial filling was calculated at the level of both atrioventricular valves and related to different factors including ventricular chamber wall thickness, heart rate, umbilical vein hematocrit and time to peak velocities values obtained at the outflow tract. Multiple stepwise regression demonstrated that the interventricular wall thickness, heart rate and hematocrit values significantly and independently affected the ratios between early and active ventricular filling from mitral and tricuspid valves. As a consequence all these factors should be taken into account in the interpretation of atrioventricular Doppler indices.
Abstract: The objective of this study was to evaluate whether Braxton-Hicks contractions induce changes in fetal heart rate variation in normal and growth-retarded fetuses. 110 uncomplicated singleton pregnancies were cross-sectionally studied as well as 16 pregnancies complicated by fetal growth retardation secondary to uteroplacental insufficiency. Fetal heart rate variability was analyzed by a commercially available computerized system (2CTG Hewlett Packard, Italy) 10 min before and 10 min after the Braxton-Hicks contraction. All the included fetal heart rate tracings fulfilled the following criteria: (1) presence of a single Braxton-Hicks contraction in the 20 min considered; (2) absence of fetal heart rate decelerations after the contraction, and (3) stable fetal heart rate behavioral pattern in the period analyzed. 82 tracings of normal fetuses were analyzed during an active fetal heart rate pattern (type B) and the remaining 28 during a quiet pattern (type A). In both patterns no significant differences in delta value, long-term irregularity, short-term variability and interval index were found before and after the contraction. All the tracings of growth-retarded fetuses were analyzed during the fetal heart rate pattern A. Short-term variation and interval index significantly decreased during the first 5 min after the contraction while no significant differences were found in the other indices investigated. The decrease in these indices was significantly more marked in those fetuses developing fetal distress within 7 days. In conclusion, Braxton-Hicks contractions induce a significant decrease of short-term variation and interval index only in growth-retarded fetuses. This can be useful in the early identification of fetal compromise in such fetuses.
Abstract: Extracardiac and cardiac flow velocity waveforms were recorded in a severely growth-retarded fetus 1 day and a few hours before fetal death. At the first scan, the typical Doppler patterns of a growth-retarded fetus were found, but the brain-sparing effect was lost at the last examination and a huge tricuspid insufficiency was demonstrated.
Abstract: Reference limits for the PI from the umbilical, middle cerebral, and renal arteries were constructed using BPD, AC, FL, and transverse cerebellar diameter as independent variables and their efficacy tested in a population of SGA fetuses. Therefore, 153 normal fetuses and 90 SGA fetuses with established dates between 20 and 40 weeks of gestation were considered. Normal fetuses showed a linear negative relationship between the PI from all the vessels investigated and all the biometric parameters considered. Although the BPD related better with the PI from the umbilical artery (r = 0.646) and the renal artery (r = 0.765) and the transverse cerebellar diameter related better with middle cerebral artery PI values (r = 0.510), no evident differences in fitting were found among the variables tested. In SGA fetuses the nomograms on BPD, AC, and FL significantly underestimated PI values in all the vessels studied when compared to the nomograms based on gestational age, while a similar ability in identifying abnormal PI values was found for nomograms based on gestational age and transverse cerebellar diameter. These newly developed nomograms based on transverse cerebellar diameter may prove useful in the evaluation of Doppler indices of fetuses with uncertain gestational age.
Abstract: The objective of this study was to establish whether variations of amniotic fluid volume induced by second-trimester amniocentesis could be detected by serial measurements of amniotic fluid index. A total of 130 singleton pregnancies undergoing second-trimester amniocentesis for genetic indications were considered. Amniotic fluid index was measured at three different time intervals: 30-60 min before amniocentesis, immediately after the procedure, and 60 min after the procedure. Serial measurements were obtained either by a single operator (n = 55) or by the three independent operators (n = 75). Significantly lower amniotic fluid index values were demonstrated immediately after amniocentesis when compared with the pre-amniocentesis and subsequent measurements in the study design with both the single and multiple operators. No statistically significant changes were found between the first amniotic fluid index measurements and those obtained 1 h after amniocentesis. These results suggest that second-trimester amniocentesis induces a temporary decrease of amniotic fluid volume detectable by serial amniotic fluid index measurements, no longer evident 1 h after the procedure.
Abstract: OBJECTIVE: Our purpose was to evaluate the incidence and patterns of chromosomal abnormalities in fetuses with absent end-diastolic velocity in umbilical artery and to analyze maternal and fetal factors associated with abnormal karyotype. STUDY DESIGN: One hundred ninety-two fetuses of known karyotype with absent end-diastolic velocity in the umbilical artery at a gestational age > 20 weeks were considered. The following potential risk factors were analyzed in a multiple logistic regression model: maternal age, gravidity, parity, gestational age at diagnosis, presence of gestational hypertension and preeclampsia, presence of fetal malformations, different biometric measurements, head/abdominal circumference ratio, amniotic fluid volume, and several Doppler index values calculated from uterine arteries, fetal heart, and fetal peripheral arteries and veins. RESULTS: Sixteen cases had an abnormal karyotype. In two cases a triploidy was present, whereas the remaining 14 cases had autosomal aberrations. The risk factors statistically significantly and independently associated with the presence of an abnormal karyotype were maternal age > 35 years, gestational age at diagnosis < 27 weeks, presence of multiple malformations, and absence of gestational hypertension and preeclampsia. All the fetuses with an abnormal karyotype but one were correctly identified by at least one risk factor. CONCLUSIONS: An abnormal karyotype is present in 8.3% of fetuses with absent end-diastolic velocity in umbilical artery and is associated with maternal and fetal risk factors. The knowledge of these factors may be useful in the management of such fetuses.
Abstract: The objective of this study was to establish whether measurement of the transverse cerebellar diameter to determine gestational age differs in small-for-gestational-age fetuses with normal or abnormal Doppler velocity waveforms. Our secondary objective was to compare the efficacy of measurement of transverse cerebellar diameter with that of femur length in pregnancy dating among small-for-gestational-age fetuses. A total of 107 small-for-gestational-age fetuses with established dates and free from structural and chromosomal abnormalities were considered for this study. According to the Doppler results, fetuses were divided into two groups: group A (n = 64), with normal Doppler values as expressed by a ratio of pulsatility indices between the umbilical artery and middle cerebral artery of <or= 95th centile of our reference limits for gestation; and group B (n = 43), with ratio of > 95th centile. Measurements of transverse cerebellar diameter and femur length were compared to previously established 95th centile prediction intervals.In both groups of small-for-gestational-age fetuses, the values for transverse cerebellar diameter were lower than in normally grown fetuses after normalization for gestational age. The difference was more evident in group A (p <or= 0.001) than in group B (p <or= 0.05). Only 68.7% of transverse cerebellar diameter values of group A fetuses fell within the normal limits for gestation, while this occurred in 90.6% of group B fetuses.When compared to the femur length, the transverse cerebellar diameter measurement appeared to be better for predicting gestational age in both groups of small-for-gestational-age fetuses (p <or= 0.001). However, this measurement may be used to estimate gestational age only in small-for-gestational-age fetuses with abnormal Doppler findings.
Abstract: The objective of this study was to evaluate differences in ductus venosus velocity waveforms between appropriate and small for gestational age fetuses by using a new index based on the ratio between systolic and atrial peak velocities. Ductus venosus velocity waveforms were cross-sectionally recorded in 164 appropriate for gestational age fetuses at 16-42 weeks of gestation and in 97 small for gestational age fetuses free from structural and chromosomal abnormalities between 24-36 weeks of gestation. Small for gestational age fetuses were divided according to the Doppler findings in arterial peripheral vessels: group A (n = 33), normal ratio between umbilical artery and middle cerebral artery Pulsatility Indices; group B (n = 41), umbilical artery/middle cerebral artery ratio > 95th centile but presence of end diastolic flow in umbilical artery; group C (n = 23), umbilical artery/middle cerebral artery ratio > 95th centile and absence of end diastolic flow in umbilical artery. Eighteen small for gestational age fetuses (10 from group B and 8 from group C) were also serially studied until delivery due to fetal distress. Ductus venosus velocity waveforms were recorded at the level of its origin from umbilical vein and the ratio between systolic and atrial peak velocities (systolic/atrial ratio) calculated. In appropriate for gestational age fetuses, systolic/atrial ratio values significantly decrease with gestation. No significant differences were found in systolic/atrial ratio between appropriate for gestational age fetuses and group A small for gestational age fetuses while, after correction for gestational age, significantly higher values were found in group B (P < or = 0.01) and group C (P < or = 0.001) fetuses. Among these fetuses, those with systolic/atrial ratio above the 95th confidence interval showed a poorer perinatal outcome. No relationships were found between systolic/atrial ratio and Pulsatility Index values from fetal arterial peripheral vessels, while a positive relationship was found with the percentage reverse flow in inferior vena cava. In fetuses serially followed, the systolic/atrial ratio progressively increased approaching the onset of abnormal fetal heart rate patterns. The systolic/atrial ratio allows the evaluation of ductus venosus hemodynamics in small for gestational age fetuses and this index may be useful in the monitoring of such fetuses.
Abstract: OBJECTIVE: Our purpose was to evaluate Doppler-detectable differences in the fetal circulation of discordant twins with a growth defect resulting from either placental insufficiency or twin-to-twin transfusion syndrome. STUDY DESIGN: Serial weekly Doppler recordings were performed for at least 3 weeks preceding delivery in 15 pairs of dichorionic twins (group A) in which the smaller twin had fetal distress (i.e., antepartum fetal heart rate late decelerations) and in 10 pairs of diamniotic and monochorionic twins (group B) in which the diagnosis of twin-to-twin transfusion syndrome was confirmed postnatally. Doppler recordings were obtained from umbilical artery, descending aorta, and middle cerebral artery, and the pulsatility index values were calculated. Furthermore, peak velocity from cardiac outflow tract and the percent of reverse flow in the inferior vena cava were calculated. For all these index values the intertwin differences (delta value) were calculated by subtracting the values obtained in the larger twin with those of the smaller twin. RESULTS: In group A significant changes of delta values were evidenced for all the parameters tested. In particular, delta values of pulsatility index from the umbilical artery and descending aorta progressively increased approaching the occurrence of late decelerations, whereas the delta value for the middle cerebral artery reached a nadir 2 weeks before delivery. Similarly, delta values of peak velocity from outflow tracts significantly decreased, whereas those of the percent reverse flow in the inferior vena cava increased during the time considered. In group B fetuses no significant intertwin differences in pulsatility index values were evidenced in the vessels investigated, resulting in absence of modifications in delta values during the time interval considered. Moreover, significant changes were found in delta values of both the peak velocity from the outflow tract and the percent of reverse flow in the inferior vena cava. However, these changes were limited to the last recording, where the former delta value increased and the latter decreased. CONCLUSIONS: Serial Doppler recordings may show hemodynamic changes in the fetal circulation of discordant twins. Different trends occur according to the underlying pathophysiologic mechanisms of the growth defect. The knowledge of these temporal changes may be useful in the management of such fetuses.
Abstract: We previously demonstrated a prognostic significance of maternal oxygen test in predicting imminent fetal distress. The purpose of this study was to investigate eventual other factors related to the length of the time interval elapsing between the Doppler diagnosis of brain sparing effect and abnormal fetal heart rate patterns. To this end we considered 101 growth-retarded fetuses free of structural and chromosomal abnormalities with a ratio between the pulsatility indices of umbilical and middle cerebral artery above the 95th centile in presence of a normal fetal heart rate pattern. The factors, other than the oxygen test, analyzed for a potential influence on this time interval were gestational age, presence of hypertension or preeclampsia, amniotic fluid index, severity of growth retardation (centile of the ultrasonographic estimated fetal weight) and 9 different Doppler indices calculated from extra- and intracardiac districts. Statistical actuarial methods were used to determine the effect of these prognostic factors on the duration of this time interval. The occurrence of abnormal fetal heart rate patterns (antepartum late heart rate decelerations) was used as censoring variable. The time interval between the entry in the study and delivery ranged from 1 to 39 days. Indications for delivery were fetal distress in 53 fetuses (52.4%) and different maternal or fetal complications in the remaining 48 fetuses.(ABSTRACT TRUNCATED AT 250 WORDS)
Abstract: OBJECTIVE: To compare uterine artery resistance index values in twin and singleton pregnancies, to examine eventual modifications of these values in twin pregnancies complicated by gestational hypertension and preeclampsia, and to determine whether resistance index values in twin pregnancies could predict the development of gestational hypertension and preeclampsia. METHODS: In a cross-sectional study, reference limits for gestation were constructed for the uterine artery resistance index (higher, lower, and mean values) in 96 uncomplicated twin pregnancies and compared to the reference limits constructed from 315 normal singleton pregnancies. Uterine artery resistance indexes obtained in 53 twin pregnancies complicated by either gestational hypertension or preeclampsia were compared with the newly established nomograms. The clinical efficacy of the uterine artery resistance index to predict hypertensive complications was evaluated prospectively in 64 twin pregnancies studied at 20-24 weeks' gestation. RESULTS: In both singleton and twin pregnancies, uterine artery resistance indexes decreased linearly with advancing gestation. However, twin pregnancies showed significantly different slopes and constant values, resulting in lower resistance indexes at all gestational ages examined. No significant differences were found when comparing resistance indexes in all patients with gestational hypertension or preeclampsia to the reference limits. Statistically significant differences were obtained for the higher (P < or = .05) and mean (P < or = .01) resistance indexes when the comparison was restricted to preeclamptic patients. In the twin pregnancies studied at 20-24 weeks' gestation, the diagnostic efficacy of the uterine artery resistance index for predicting the development of gestational hypertension and/or preeclampsia was disappointingly low (k < 0.10). CONCLUSIONS: Resistance index values in the uterine artery are lower in twin pregnancies than in singleton pregnancies. Gestational hypertension and preeclampsia may occur in twin pregnancies despite normal uterine artery velocity waveforms, suggesting a limited role of this measurement in the management and prediction of hypertensive complications in twin pregnancies.
Abstract: Intrauterine growth retardation continues to be one of the major problems in obstetrics and still greatly contributes to perinatal mortality and morbidity. This paper reviews the role of Doppler ultrasonography in the antenatal assessment of fetuses with intrauterine growth retardation. Recent developments in this field are described with particular emphasis on the pathophysiologic background of the hemodynamic modification of fetuses with intrauterine growth retardation. Doppler ultrasonography allows the prediction of the development of intrauterine growth retardation in selected populations and the identification among a population of small-for-gestational-age fetuses, those really at risk of unfavorable outcome. Finally, the modifications occurring after the establishment of the growth retardation with the progression of fetal deterioration are described in an attempt to clarify the natural history of this condition. To this end, the longitudinal changes of Doppler indices of placental vessels, fetal arterial vessels, fetal heart, and venous circulation are described, and their complex interrelationship is analyzed. The knowledge of these mechanisms may be useful in deciding the timing of delivery.
Abstract: On the basis of the data obtained in sheep fetuses showing a high interdependence between umbilical vein oxygenation and ductus venosus flow, we investigated the effect of maternal hyperoxygenation on ductus venosus velocity waveforms in normal third-trimester human fetuses. Ductus venosus velocity waveforms were recorded by using color and pulsed Doppler ultrasonography before and after 15 min of maternal administration of humidified 60% oxygen. During maternal hyperoxygenation, there was a significant increase of both estimated peak velocities during systole, diastole and atrial contraction and the mean temporal velocity during the total cardiac cycle and systolic and diastolic portions. On the other hand, during maternal hyperoxygenation, no significant changes were found in fetal heart rate or in the ratios between peak velocities and mean temporal velocities during systole and diastole. These findings suggest a close relationship between fetal oxygenation and ductus venosus velocity waveforms that may be useful in monitoring fetal hypoxemia.
Abstract: OBJECTIVES: Our objectives were to evaluate the time interval elapsing between the occurrence of absent end-diastolic velocity in the umbilical artery and either the development abnormal fetal heart rate patterns or delivery and to establish the maternal and fetal factors that may affect this interval. STUDY DESIGN: Thirty-seven fetuses free of structural and chromosomal abnormalities in which the development of absent end-diastolic velocity in umbilical artery was evidenced by serial Doppler recordings were studied. At the first occurrence the following factors were considered: gestational age, presence of hypertension or preeclampsia, amniotic fluid index, severity of growth retardation, and 10 different Doppler indices calculated from extracardiac and intracardiac vascular districts. Actuarial statistical methods were applied, with the occurrence of antepartum late heart rate deceleration as the censoring variable. RESULTS: The interval between the first occurrence of absent end-diastolic velocity in umbilical artery and delivery ranged from 1 to 26 days. Indications for delivery were the development of antepartum late heart rate decelerations in 23 fetuses (62.1%) and different maternal or fetal complications in the remaining 14 fetuses. Multivariate analysis revealed that gestational age and the presence of hypertension and pulsations in umbilical vein were the dominant factors in determining the length of this time interval. CONCLUSION: The duration of the time interval between the occurrence of absent end-diastolic velocity in umbilical artery and abnormal heart rate pattern differs considerably among fetuses, and it is mainly determined by gestational age and presence of maternal hypertension and pulsations in umbilical vein.
Abstract: OBJECTIVES: To determine the growth patterns of the fetal heart and the development of cardiac function during gestation in fetuses of diabetic mothers, and to compare these findings with those of normal fetuses. METHODS: Serial M-mode and Doppler echocardiographic recordings were made at 4-week intervals in 14 fetuses of well-controlled type I insulin-dependent diabetic mothers and in ten control fetuses at 20-36 weeks' gestation. The following variables were measured: interventricular septal thickness, left ventricular wall thickness, right ventricular wall thickness, ratio between the peak velocities during early passive ventricular filling and active atrial filling at the level of the atrioventricular valves, peak velocities, and time to peak velocity at the level of the ascending aorta and pulmonary artery. RESULTS: In both groups of fetuses, all of the indices increased linearly with gestation. However, fetuses of diabetic mothers showed significant differences in the slope and intercept values for the function describing the growth of the interventricular septum (P less than or equal to .001) and the right and left ventricular wall thicknesses (P less than or equal to .01), resulting in accelerated cardiac growth. The function describing the development of the ratios between early and active ventricular filling showed differences in slope and intercept values at the level of both the mitral (P less than or equal to .001) and tricuspid valves (P less than or equal to .001), resulting in a lower rate of increase during diabetic pregnancy when compared with control fetuses. Significantly higher intercept values were found in the functions describing the increase of peak velocities in the aorta and pulmonary artery in fetuses of diabetic mothers (P less than or equal to .01), whereas the slopes were similar to those of control fetuses. No differences were found in the time to peak values between the groups of fetuses. No relationships were found between the echocardiographic results and the metabolic control of pregnancy or fetal characteristics. CONCLUSIONS: This study suggests that strict maternal diabetes control does not exclude accelerated fetal cardiac growth and abnormal development of cardiac function.
Abstract: A cystic lesion in the anterior upper part of the abdomen was detected in utero by ultrasonography. Color and pulsed Doppler studies performed over the mass revealed a marked turbulent flow through the cystic lesion in connection with the umbilical vein, suggesting the existence of an intra-abdominal ectasia of the umbilical vein.
Abstract: Thirty-six growth-retarded fetuses selected from a population of 214 cases were studied by Doppler ultrasonography at weekly intervals for at least 4 weeks between the diagnosis of Doppler abnormalities suggestive of the existence of the brain-sparing effect (ie, ratio between umbilical artery and middle cerebral artery pulsatility indexes [PIs] above the 95th percentile of our reference limits) to the onset of antepartum late fetal heart rate (FHR) decelerations. Recordings were made from the umbilical artery, descending aorta, renal artery, internal carotid artery, and middle cerebral artery and the PIs were calculated. Statistically significant changes in PI occurred in all the vessels studied. However, different trends were found when the modifications in cerebral vessels were compared with those in fetal peripheral vascular beds and in the umbilical artery. In cerebral arteries, a nadir of vasodilatation was reached 2 weeks before the onset of antepartum late FHR decelerations, whereas significant changes in the peripheral and umbilical vessels occurred close to the onset of abnormal FHR patterns. This study demonstrates that despite a brain-sparing effect, there are further Doppler-detectable modifications in fetal circulation that differ between the cerebral and peripheral vascular beds.
Abstract: Reference ranges of inferior vena cava flow velocities were constructed from a cross-sectional study of 118 appropriate-for-gestational-age fetuses of 18 to 40 weeks of gestation. Blood flow velocity waveforms were recorded with color and pulsed Doppler equipment. Peak velocities and time velocity integrals were measured from inferior vena cava during systole, early diastole, and atrial contraction. The systolic-to-diastolic ratios between the peak velocities and time velocity integrals were calculated, and the reverse flow with atrial contraction was quantified as the percentage of forward flow (percentage of reverse flow). Recordings were also obtained from 79 small-for-gestational-age fetuses free of structural and chromosomal abnormalities, divided into three groups according to umbilical artery velocity waveforms: normal pulsatility index values (group 1, n = 26), pulsatility index greater than 95th percentile of our reference limits but presence of end-diastolic velocities (group 2, n = 33), and absence of end-diastolic velocities (group 3, n = 20). Fourteen fetuses of groups 2 and 3 were also studied at weekly intervals until the onset of antepartum late heart rate decelerations. In appropriate-for-gestational-age fetuses no changes were evident in peak velocities and time velocity integrals ratios, whereas the percentage of reverse flow significantly decreased with gestation. No significant differences were found between these values and those obtained in small-for-gestational-age fetuses of group 1. A significant increase of peak velocities and time velocity integrals ratios and of percentage of reverse flow was evidenced in fetuses of both group 2 and 3. The fetuses of groups 2 and 3 with a percentage of reverse flow above the 95% confidence interval showed a poorer perinatal outcome when compared with the fetuses of the same groups but with values inside the normal range. In the 14 fetuses longitudinally followed up until the onset of late heart rate decelerations a significant and progressive increase of peak velocities and time velocity integrals ratios and percentage of reverse flow was evidenced in spite of minimal changes in the pulsatility index from both umbilical artery and different peripheral fetal vessels. This study presents evidence that in small-for-gestational-age fetuses with abnormal Doppler-measured placental resistance the modified flow velocity patterns in the inferior vena cava seem to deteriorate progressively with advancing gestation.
Abstract: OBJECTIVES: The purpose of this study was to establish the incidence of umbilical vein pulsations in normal early pregnancies and to evaluate whether these pulsations are related to Doppler-measured vascular resistances in umbilical artery or central venous flow patterns. STUDY DESIGN: We performed a cross-sectional study on 257 uneventful pregnancies at 7 to 16 weeks of gestation by means of transvaginal color and pulsed Doppler ultrasonography. Blood flow velocity waveforms were recorded from the umbilical artery, umbilical vein and, in 48 cases, also from fetal inferior vena cava. RESULTS: Pulsations in the umbilical vein were evidenced in all cases until 8 weeks. From this gestational age on pulsations progressively disappeared, becoming completely absent at greater than or equal to 13 weeks. The incidence of pulsations in the umbilical vein was unrelated to umbilical artery pulsatility index values, the incidence of absent end-diastolic flow in umbilical artery, and fetal heart rate. In the inferior vena cava, reverse flow during atrial contraction was significantly higher (p less than or equal to 0.002) in cases with umbilical vein pulsations than in those cases without pulsations at a similar gestational age. CONCLUSIONS: Pulsations in the umbilical vein are physiologically present during the first trimester of pregnancy and seem to be related to inferior vena cava flow patterns.
Abstract: Blood flow velocity waveforms were recorded from different vascular districts including umbilical artery, descending aorta, renal artery, internal carotid artery and middle cerebral artery in a population of 120 small for gestational age fetuses free from structural and chromosomal abnormalities. The pulsatility index from each vessel as well as the ratios between the pulsatility indices from peripheral and cerebral vessels were calculated and related to perinatal outcome. The pulsatility index of middle cerebral artery resulted the most efficient measurement to predict the development of perinatal adverse outcome when each vessel was considered singularly, however, better results were achieved when the ratios between pulsatility indices were related to perinatal outcome; this is mot evident for the ratio between the pulsatility indices of umbilical artery and middle cerebral artery. Our results suggest the usefulness of this ratio in differentiating small for gestational age fetuses at risk of unfavorable outcome.
Abstract: Blood-flow velocity waveforms are altered in several peripheral vascular beds of fetuses whose intrauterine growth is retarded because of placental insufficiency. We investigated these concomitant changes in cardiac function. Color and pulsed Doppler echocardiographic recordings were performed in 124 fetuses with intrauterine growth retardation. These fetuses were free of structural and chromosomal abnormalities and were characterized by increased umbilical artery resistance and reduced middle cerebral artery resistance. Twenty-four of these fetuses were also studied at weekly intervals until the onset of antepartum late heart rate decelerations. Blood-flow velocity waveforms were obtained from the aortic and pulmonary valves, and the following variables were measured: peak systolic velocity, time to peak velocity, the product of time velocity integral multiplied by heart rate, left and right cardiac output, and the right/left ratios of the product of time velocity integrals multiplied by heart rate and cardiac output. When compared with previously established norms, both aortic and pulmonary peak systolic velocities and pulmonary time to peak velocity were reduced; aortic time to peak velocity increased. Left cardiac output and the product of the aortic time velocity integral multiplied by the heart rate increased and right cardiac output and the product of the pulmonary time velocity integral multiplied by the heart rate decreased, resulting in reduced right/left ratios. In the 24 fetuses studied longitudinally, time to peak velocities and the right/left flow ratios remained stable. However, aortic and pulmonary peak velocities and cardiac output declined significantly in contrast to an expected rise with advancing gestation. The fall in cardiac output and aortic and pulmonary peak velocities was directly related to umbilical artery pH at birth. This study provides evidence of a modified cardiac function that seems to deteriorate progressively with the advancing gestation of fetuses with intrauterine growth retardation.
Abstract: In order to establish the growth patterns of fetal limbs, measurements of femur, humerus, tibia, fibula, radius and ulna were made by ultrasound and related to gestational age. To this end, 2317 normal singleton pregnant women were studied cross-sectionally at 13-40 weeks of gestation. Patients were selected on the basis of a certain last menstrual period, history of regular cycles and at least one ultrasound scan before 16 weeks confirming gestational age. Linear growth of all limb measurements was observed between 13 and 28 weeks of gestation. From this gestational age onwards, a flattening of the growth curve was seen. A second-degree polynomial equation turned out to be the best model to describe this phenomenon. The measurements of all six fetal long bones showed a high correlation with menstrual age (r >or= 0.99). The femur displayed the largest mean weekly increments (2.8 mm per week from 13 to 28 weeks and 1.7 mm per week from 29 to 40 weeks of gestation) and the radius had the smallest (2.08 mm per week from 13 to 28 weeks and 1.25 mm per week from 29 to 40 weeks' gestation). Considering inter and intraoperator variations and the weekly increment of fetal long bone length, a correct evaluation of limb growth is possible for the femur every week before 28 weeks and every 2 weeks after 28 weeks. For the remaining limb bones, a correct evaluation is possible every 2 weeks at all gestational ages.
Abstract: A longitudinal study was performed on 35 healthy fetuses in order to evaluate the developmental course of behavioural transitions during the last trimester of pregnancy. A progressive decrease in the duration of transitions as a function of gestational age was evidenced for both transitions from 1F to 2F and transitions from 2F to 1F. Concerning the sequence in change of behavioural variables (fetal heart rate, fetal eye movements and fetal gross body movements) a random distribution was found until 30 weeks for 1F to 2F transitions and until 34 weeks for 2F-1F transitions. After these gestational ages fetal heart rate and fetal gross body movements respectively become the first variable to change during 1F-2F and 2F-1F transitions. Reference values for these parameters are calculated in order to provide a basis for the diagnosis of behavioural abnormalities in high risk fetuses.
Abstract: In a cross-sectional study, umbilical artery velocity waveforms were recorded in 214 low-risk pregnancies at 7 weeks to 16 weeks, menstrual age, by means of transvaginal color and pulsed Doppler ultrasonography. In all the cases studied, end diastolic velocities were absent until the 10th week. From this age onward end diastolic velocities were present in a percentage of pregnancies, progressively increasing with gestation and reaching 100% at 15 weeks. Similarly, the percentage of cardiac cycles in which end diastolic velocities were absent progressively decreased with advancing menstrual age. The normal range for the pulsatility index was constructed and a quadratic function was found to optimally fit its fall during gestation. No differences in pulsatility index values were found at these menstrual ages in 12 pregnancies that later developed intrauterine growth retardation and/or pregnancy-induced hypertension, suggesting that placental alterations causing abnormalities in umbilical velocity waveforms occur later in gestation.
Abstract: One thousand singleton low-risk pregnancies were cross-sectionally studied at 36-40 weeks gestation with continuous-wave Doppler ultrasonography in order to assess its usefulness as an antepartum monitoring technique for the identification of fetuses at risk of developing an adverse outcome. Uterine artery and umbilical artery S/D values were measured and related to fetal outcome. Results were compared with those of the nonstress test. No significant differences in fetal outcome, with the exception of birth weight, were found between patients with normal and abnormal uterine S/D values. In pregnancies with abnormal umbilical S/D values, a higher incidence of cesarean section for fetal distress and lower birth weight were observed. Moreover, those newborns more frequently had complications such as low 5-minute Apgar score, requiring resuscitation and admission to the intensive care unit. When compared to nonstress test, umbilical velocimetry showed a higher efficiency in identifying fetuses at risk for adverse outcome.
Abstract: A transvaginal color and pulsed Doppler study was performed on 330 pregnancies at 7-16 weeks of gestation. Blood flow velocity waveforms were recorded from the main uterine arteries and their branches (arcuate and trophoblastic vessels) and from the umbilical arteries. The systolic/diastolic velocity ratio and the pulsatility index were calculated as indices of vascular resistance, respectively, at uterine and umbilical levels. A total of 282 patients had an uneventful pregnancy outcome, 19 developed an early pregnancy failure (missed abortion, n = 8; anembryonic pregnancy, n = 11) and 29 developed later complications such us hypertension (n = 10), fetal growth retardation (n = 13) or both n = 6). In normal pregnancies, Doppler-measured vascular resistances significantly decreased with advancing gestation at the level of both uterine and umbilical circulations. When the Doppler indices of the patients with early pregnancy failure or with later complications were compared to those of normal pregnancies, no evident differences were found in either of the vascular districts considered. However, in the patients who developed hypertension and/or fetal growth retardation, abnormal velocity waveforms were frequently present in uterine and umbilical arteries during second- or third-trimester examinations. Our results suggest a limited clinical value of Doppler velocimetry in early pregnancy.
Abstract: Renal blood flow velocity waveforms were recorded by Doppler ultrasonography in 114 growth-retarded fetuses and in 97 post-term fetuses. The pulsatility index (PI) values were compared with our reference limits for gestational age and related to the amount of amniotic fluid. Growth-retarded fetuses showed significantly increased PI values compared with normally grown fetuses, and this difference was particularly evident in cases of oligohydramnios. Furthermore, there was a significant negative correlation between the increase in PI and the amniotic fluid volume. Post-term fetuses showed no significant differences in PI values compared with term fetuses and no significant correlation between the amount of amniotic fluid and PI values.
Abstract: Cardiac function was cross-sectionally studied by means of M-mode and Doppler echocardiography in 40 fetuses of mothers with well-controlled insulin-dependent diabetes at 20 to 38 weeks of gestation. These variables were measured: interventricular septal thickness, ratio between the peak velocities during early passive ventricular filling and active atrial filling at the level of the atrioventricular valves, peak velocities, and the time to peak velocity at the level of the ascending aorta and the pulmonary artery. The values obtained were compared with our reference limits for gestation. A significant increase of interventricular septal thickness that was unrelated to maternal glycosylated hemoglobin levels was evidenced. Early passive ventricular filling/active atrial filling ratios were significantly lower in fetuses of diabetic mothers than in control fetuses. These differences were significantly related to interventricular septal thickness. No significant modifications were found in either aortic or pulmonary peak velocities or in time to peak velocity values. These findings suggest that in spite of an adequate metabolic control an interventricular septal hypertrophy that affects cardiac diastolic function develops in fetuses of diabetic mothers.
Abstract: The cardiac output was measured by means of Doppler echocardiography in four anencephalic fetuses during the late second or third trimester of pregnancy. Anencephalic fetuses showed a higher dominance of right ventricular output when compared to healthy fetuses, suggesting that the relationship between brain mass and body weight affects the distribution of cardiac output.
Abstract: In order to assess whether maternal hyperoxygenation induces modifications of Doppler-measured velocity waveforms across atrioventricular valves, 15 healthy and 15 growth-retarded fetuses were studied in basal conditions and during the maternal administration of 60% humidified oxygen. Recordings were performed at 5-min intervals before, during and after maternal oxygen administration. In basal conditions, growth-retarded fetuses exhibited significantly lower ratios between the velocities during early passive ventricular filling and active ventricular filling (E/A ratio) at the level of both mitral and tricuspid valves when compared to healthy fetuses. Furthermore in healthy fetuses the velocity time integral across the tricuspid valve always slightly exceeded that across the mitral valve, whilst growth-retarded fetuses showed an inversed ratio between these velocities. During oxygen administration no changes were found between the two groups of fetuses with regard to the E/A ratios. Similarly the velocity time integrals were unaffected by oxygen administration in the healthy fetuses. Besides growth-retarded fetuses exhibited significant temporary modifications during oxygen administration as expressed by an increase in the velocity time integral across the mitral valve associated with a decrease of that across the tricuspid. These changes result in an inversion of the ratio between transtricuspid and transmitral velocity time integrals reaching values similar to those of healthy fetuses. Short-term oxygen administration affects the intracardiac flow redistribution present in growth-retarded fetuses bringing it to a pattern similar to that of healthy fetuses whereas the E/A ratios were not affected by the treatment.
Abstract: A system based on an IBM compatible personal computer is described for the computerized analysis of the cardiotocograms. The system performs a quantification of both fetal heart rate and uterine contractions providing automatically several variables including heart rate baseline; number, duration and area of accelerations and decelerations; latency time between decelerations and uterine contractions; uterine resting tone; number, duration and area of contractions. The computerized description was compared to the visual analysis of the cardiotocogram and a good agreement was evidenced. This system was applied to the analysis of heart rate variability in order to recognize the different patterns characterizing fetal behavioral states. Up to now, however, the results obtained in this latter application are not sufficiently accurate and do not allow a reliable automatic recognition of heart rate patterns.
Abstract: A study was made in order to assess whether the combined use of color flow mapping and conventional pulsed Doppler could improve the accuracy of blood flow velocity waveform analysis in fetal and placental circulations. Fifty patients were studied at 18 to 20 or 26 to 28 weeks of gestation by two trained investigators by means of either conventional Doppler or conventional Doppler plus color flow mapping. Recordings were performed at the level of the uterine arteries, umbilical artery, descending aorta, and internal carotid artery. The experimental procedure was repeated the following day with the patients undergoing the alternate technique of recording. In all the vascular districts investigated, color flow mapping allowed us to obtain a higher number of reliable recordings, to shorten the observation time, and to reduce the intra- and interobserver coefficient of variations.
Abstract: The changes in fetal blood flow velocity waveforms during maternal administration of 60% humidified oxygen were assessed by Doppler ultrasonography in 45 post-term fetuses. During oxygen treatment, nine fetuses exhibited temporary increases (24.3 +/- 2.0% [1 standard deviation] above pretreatment values) in the pulsatility index at the level of internal carotid artery. Although no significant changes (2.9 +/- 5.1%) were found in the remaining 36 fetuses. In this former group a higher incidence of emergency cesarean delivery due to fetal distress and more neonatal complications were observed. Also, meconium staining of the amniotic fluid and low 1- and 5-minute Apgar scores occurred more frequently in the group of fetuses who responded to maternal oxygen administration. An increase of at least 20% in the pulsatility index of internal carotid artery during maternal hyperoxygenation may be a useful marker of adverse outcome in post-term fetuses.
Abstract: The time to peak velocity was measured at the level of the ascending aorta and pulmonary artery by Doppler echocardiography in 38 small-for-gestational age (SGA) fetuses before and during maternal hyperoxygenation. The values were compared to a reference range derived from the study of 142 appropriate-for-gestational age (AGA) fetuses. In the SGA fetuses the time to peak velocity at the level of pulmonary artery was significantly lower and at the level of the aorta significantly higher than in AGA fetuses. During maternal hyperoxygenation the aortic time to peak velocity decreased towards normal range but there was no significant change at the level of the pulmonary artery. These results may indicate variations of aortic and pulmonary pressures in SGA fetuses that can be partially modified by maternal hyperoxygenation and which may be associated with changes in the peripheral resistance of the cerebral circulation.
Abstract: In 12 fetuses from pregnancies with red blood cell isoimmunization Doppler velocity waveforms were recorded at the level of atrioventricular valves immediately before and at 15-minute intervals for 2 hours after the intravascular transfusion. The left and right cardiac outputs, the ratio between the peak velocities during early passive ventricular filling and active atrial filling at the level of both ventricles as well as the heart rate were calculated. Before transfusion, the left and right cardiac outputs were significantly higher than reference ranges for gestation that were constructed from the cross-sectional study of 187 normal pregnancies. After transfusion there was a significant temporary fall in right and left outputs associated with increased ratios between the peak velocities during early passive ventricular filling and active atrial filling. Within 2 hours after transfusion both parameters returned toward the normal range. In addition, no significant changes were found for fetal heart rate values before and after transfusion. The fall of cardiac output was significantly related to the amount of expansion of the feto-placental volume.
Abstract: Doppler velocity waveforms from atrioventricular valves were recorded in 20 healthy fetuses at 36--38 weeks of gestation during both behavioural states 1F (quiet sleep) and 2F (active sleep). No significant changes were found in the ratios between the velocities during early passive ventricular filling and active ventricular filling (E/A ratios) at the level of both mitral and tricuspid valves when the measurements obtained during states 1F and 2F were compared. Moreover, during state 2F the left ventricular output increased and the right ventricular output decreased, resulting in a marked modification of the right to left cardiac output ratio. Our data suggest a redistribution of cardiac output in favour of the left side of the heart during state 2F.
Abstract: In a cross-sectional study of 1556 uncomplicated pregnancies velocity waveforms were recorded at the level of fetal umbilical artery, descending aorta, renal artery, internal carotid artery and middle cerebral artery. Reference limits for the Pulsatility Index of each vessel were constructed by regression analysis and a progressive fall during gestation was evidenced in all the vascular districts investigated with the exception of descending aorta. Furthermore we calculated the ratios between Pulsatility Index values of cerebral and peripheral vessels which may be relevant for the early diagnosis of the haemodynamic abnormalities occurring during the brain sparing effect.
Abstract: The significance of fetal cerebral blood flow analysis in the prediction of neonatal neurologic outcome was investigated on 87 fetuses at risk for chronic hypoxia. Blood flow velocity waveforms were recorded from the fetal internal carotid artery immediately before cesarean section; newborns underwent neurologic follow-up until discharged from the neonatal division. Neonatal outcome was considered abnormal in presence of a postasphyxial encephalopathy. Receiver operating characteristic curves were used to demonstrate the efficacy of fetal cerebral blood flow velocity waveform analysis as a predictor of neonatal outcome. A value of the pulsatility index from the internal carotid artery below the second standard deviation of our range of normality was found to be a powerful indicator of the development of neonatal neurologic abnormalities (Cohen's Kappa index = .58). These results were particularly evident in fetuses with a birthweight above 2500 g in which a specificity of 93.7%, a sensitivity of 75%, and an accuracy of 89.7% were achieved.
Abstract: The transitions, i.e. time intervals between two different behavioural states, were studied in 10 healthy and 10 growth retarded fetuses (IUGR) in near term pregnancies. In healthy fetuses, transitions usually lasted less than 3 min whereas IUGR fetuses showed a longer duration when compared to healthy fetuses. Moreover, a significant trend in the change of state variables (fetal heart rate, fetal eye movements and fetal gross body movements) was evident in healthy fetuses: fetal heart rate was the first variable to change in transitions from 1F to 2F and the last variable to change in transitions from 2F to 1F. On the other hand IUGR fetuses showed a random sequence in order of change. These findings were substantiated by the intraindividual consistency evidenced in repeated recordings. In conclusion the analysis of transitions differentiates between healthy fetuses and those affected by IUGR.
Abstract: The changes in fetal hemodynamics during maternal administration of 60% humidified oxygen were assessed by Doppler ultrasonography in 15 growth retarded fetuses characterized by abnormal blood flow velocity waveforms. During oxygen treatment, nine fetuses exhibited temporary hemodynamic modifications as expressed by a recovery toward the normal range of vascular impedance in the descending aorta and internal carotid artery, whereas no changes were found in the remaining six fetuses. In this latter group, a rapid deterioration of fetal condition occurred and all the fetuses were delivered by emergency cesarean section within 9 days from the Doppler examination. The absence of recovery of vascular resistance during acute maternal oxygen administration seems therefore to be a useful marker of imminent acute distress in fetuses with growth retardation secondary to chronic hypoxia.
Abstract: Doppler blood flow velocity waveforms from fetal umbilical artery, descending aorta, internal carotid artery and maternal uterine arteries were recorded in 50 fetuses near term undergoing cesarean section before the onset of labor in order to evidence eventual relationships with the fetal acid-base status. The primary indications for cesarean section were in 16 cases an elective repeated cesarean section and in the remaining cases maternal hypertension often associated with fetal growth retardation and/or fetal distress. The technique of anesthesia was strictly standardized and fetal blood gas levels and acid-base status were analyzed in umbilical artery and vein immediately after birth. A significant correlation was found between the pulsatility index from internal carotid artery and the pO2 levels in umbilical vein (r = 0.87; p less than or equal to 0.001). Similar relationships were found between the pulsatility index from descending aorta and the pCO2 (r = 0.78; p less than or equal to 0.001), base excess (r = 0.72; p less than or equal to 0.001) and pH (r = 0.80; p less than or equal to 0.001) levels in umbilical artery. It is suggested that Doppler ultrasound could be useful in the diagnosis of fetal hypoxia and acidosis.
Abstract: The fetal behaviour of 15 asymmetrical intrauterine growth retarded (IUGR) fetuses was compared to that of a control group of healthy fetuses. Fetuses underwent simultaneous cardiotocographic and ultrasonographic examinations for 2 consecutive hours at 36-38 weeks' gestation. Behavioural states analysis was carried out by means of a computerized system (Digital PDP 11) that allowed the recording of several fetal variables including heart rate (FHR), gross body movements (FM), eye movements (FEM) and breathing movements (FBM). FHR was classified in four different patterns (FHRP) according to Nijhuis et al.; fetal movements were automatically synchronized with FHR and grouped for each FHRP. Several quantitative parameters (i.e. incidence, mean duration, lag time, % time spent moving) were then computed for each movement. There were no statistical differences in the distribution of FHRP between healthy and IUGR fetuses. On the other hand quantitative differences were found when the movements investigated were related to FHRP. In IUGR fetuses FEM were mainly represented by low frequency movements (IEM) during both low (FHRP A) and high variability (FHRP B) FHRP, whereas healthy fetuses exhibited mostly rapid eye movements (REM) during FHRP B and absent type of FEM during FHRP A. Moreover IUGR fetuses showed a reduction of state 1F (quiet sleep) and an increase of periods of no coincidence between behavioural state variable when compared to the control group fetuses. These findings, therefore suggest the existence of quantitative differences in fetal behaviour in asymmetrical IUGR fetuses when compared to healthy fetuses.
Abstract: A prospective longitudinal study determined the physiological patterns of blood flow velocity waveforms in normal and in small-for-gestational-age (SGA) fetuses. Using a Pulsed Doppler Duplex system, 125 normally grown fetuses and 35 SGA fetuses were studied longitudinally at between 27 and 42 weeks gestation. In normal fetuses the ratio between the E velocity (early passive ventricular filling) and the A velocity (active ventricular filling during atrial contraction) increased progressively during pregnancy in both transmitral and transtricuspid waveforms, approaching 1 at term. In SGA fetuses, the E/A ratios did not increase during pregnancy and the values obtained were significantly lower than in normal fetuses. The ratio between the transtricuspid and transmitral mean temporal velocities remained almost constant throughout pregnancy in the normal fetuses with transtricuspid velocity slightly exceeding the transmitral velocity. On the other hand, in SGA fetuses the ratio between the mean temporal velocities was inversed with the transmitral velocity progressively greater than the transtricuspid velocity suggesting the existence of intracardiac haemodynamic changes in these fetuses.
Abstract: The purpose of this investigation was to compare the efficacy of conventional ultrasonographic measurements (i.e. head to abdomen circumference ratio, amount of amniotic fluid) with Doppler ultrasonography in the differential diagnosis of small-for-gestational age (SGA) fetuses. Blood flow velocity waveforms were recorded from the umbilical artery descending aorta and internal carotid artery in 121 intrauterine growth-retarded fetuses and the pulsatility index was evaluated as an index of vascular impedance. Conventional ultrasonographic measurements were of limited usefulness in the differential diagnosis, whereas the ratio between the pulsatility indexes from umbilical and carotid arteries proved to be a good index for discriminating SGA fetuses due to low growth potential (congenital infections, structural anomalies, chromosomal abnormalities, constitutional factors) from those caused by placental dysfunction (specificity 96.6%, sensitivity 89%, positive predictive value 98.7%, negative predictive value 74.3% and accuracy 90.9%.
Abstract: To determine whether maternal oxygen administration affects fetal hemodynamics, we investigated 10 healthy fetuses and 10 growth-retarded fetuses near term by means of Doppler ultrasonography. The growth-retarded fetuses were characterized by abnormal blood flow velocity waveforms. Velocity waveforms were simultaneously recorded at 5-minute intervals from the fetal descending aorta and internal carotid artery before, during, and after maternal oxygen administered through a face mask that delivered 60% oxygen. The pulsatility index was calculated. During oxygen treatment growth-retarded fetuses showed significant temporary hemodynamic modifications as expressed by changes of pulsatility index values that increased in the internal carotid artery and decreased at the level of the descending aorta. On the other side no changes were found in healthy fetuses. These findings suggest that maternal oxygen administration can modify fetal hemodynamics in cases of growth retardation associated with abnormal blood flow velocity waveforms.
Abstract: A computerized system which simultaneously acquires and quantifies several ultrasonically detected fetal activities, including gross body movements, breathing movements, and eye movements, was developed in order to obtain additional quantitative data on fetal behaviour. Movements were automatically related to fetal heart rate allowing computation of their mean incidence, duration, lag time and percentage time spent moving during different heart rate patterns. The incidence of various behavioural states was also calculated. The study of 15 healthy fetuses near term revealed the existence of statistically significant differences in these parameters between low and high variability patterns of fetal heart rate suggesting a quantitative modulation of fetal movements by behavioural states.
Abstract: Sixty high-risk pregnancies were studied in order to define the validity of the analysis of utero-placental blood flow velocity waveforms in early screening for developing hypertensive diseases. Recordings were obtained at 18-20 weeks gestation, in normotensive patients, using a pulsed duplex Doppler system at the level of uterine vessels. The patients (n = 22) who developed hypertension showed a higher resistance index value (p less than 0.001) than normotensive patients (n = 38). The validity of uteroplacental waveform analysis was as follows: specificity = 84.2%; sensitivity = 63.6%; positive predictive value = 70%; negative predictive value = 80%; accuracy = 76.6%. The high specificity attained suggests that this test can adequately identify, among a high-risk population, patients destined to remain normotensive during pregnancy.
Abstract: The fetal behaviour of asymmetrical growth retarded fetuses was compared with that of a control group of healthy fetuses. Fetuses underwent simultaneous cardiotocographic and echographic examinations for two consecutive hours at 36-38 weeks of gestation. The distribution of gross fetal body movements, fetal breathing movements and fetal eye movements was analysed during the different fetal heart rate patterns. Furthermore, the incidence and organization of fetal behavioural states was investigated. The degree of vascular peripheral resistance was also evaluated by means of pulsed doppler ultrasonic equipment. Growth retarded fetuses were divided into two groups on the basis of the presence or absence of end diastolic flow in the fetal thoracic descending aorta. Growth retarded fetuses showed a delay in the integration of behavioural patterns and a lower coincidence of behavioural states. These findings are particularly evident in the fetuses with a severe increase of peripheral vascular resistance (absence of end diastolic flow in descending aorta). Thus, we suggest that a delay in central nervous system development is present in asymmetrical growth retarded fetuses and that there is a possible relationship of this delay to the degree of peripheral vascular resistance.
Abstract: A longitudinal study was carried out on 30 healthy fetuses in order to assess the modifications of fetal blood flow throughout pregnancy. The pulsatility index was evaluated at two-week intervals by means of pulsed Doppler equipment. In the umbilical artery measurements were performed from 20 weeks onwards, whereas in the descending aorta and internal carotid artery analysis started from 26 weeks onwards. A decrease of the pulsatility index in umbilical artery and in the ratio between the pulsatility indexes in umbilical artery and internal carotid artery was found over the second half of pregnancy.
Abstract: Fetal heart rate and fetal movements were recorded over a 24-hour interval in a totally adrenalectomized pregnant woman at term. Cortisol, ACTH, unconjugated estriol and 17 beta-estradiol were contemporaneously measured every 2 h in the maternal peripheral plasma. Owing to the substitution therapy the patient showed a loss of circadian variations of all the hormones investigated. Moreover, the circadian rhythms of fetal heart rate and fetal movements, usually present at term, were no longer evident. We can thus suggest that the circadian variations of plasma maternal cortisol could affect the alternations of fetal behaviour.
Abstract: Fetal behavior was studied after intravenous administration of either 0.4 mg of naloxone or an equal volume of saline solution in 54 healthy pregnant women near term. The number, duration, and amplitude of fetal heart rate accelerations increased after naloxone injection. The incidence of both gross fetal body movements and fetal breathing movements increased, especially in the first hour after naloxone administration. The distribution of fetal behavioral states was modified with a prevalence of active sleep and active awake states compared to the quiet sleep state. These data suggest that endorphins could be involved in the modulation of fetal behavior.
Abstract: In order to verify if fetal behavioural states could affect cardiac parameters, thirty-one healthy fetuses were studied near term. We evaluated systolic time intervals (pre-ejection period and ventricular ejection time), M-mode parameters (fractional shortening and mean circumferential shortening) and Doppler flow velocities (mean peak velocity of aortic and pulmonary arteries) of left and right ventricles. Both fetal breathing movements and fetal heart rate patterns seem to modify these parameters with an increase of cardiac contractility during active phases of fetal behaviour.
Abstract: Behavioral states observations were carried out in 12 hydrocephalic fetuses by means of a computerized system. Recordings of behavioral parameters, including fetal heart rate, gross body movements, breathing movements and eye movements, were performed at 2-week intervals from 30 weeks of gestation onwards. The hydrocephalic fetuses showed quantitative and qualitative differences in their motor behavior in comparison to healthy fetuses of equivalent gestational age. Similarly the appearance of behavioral states was delayed in hydrocephalic fetuses. Furthermore, an increased discordance between the behavioral parameters was evidenced. The degree of discordance seems to be related to the severity of neonatal outcome suggesting a possible estimation of CNS dysfunction by means of behavioral state analysis.
Abstract: A cerebral midline cystic lesion was detected by real-time ultrasound in utero in the absence of other congenital abnormalities. Pulsed Doppler ultrasound assessment of fetal circulation demonstrated normal peripheral and intracardiac hemodynamics associated with decreased cerebral vascular resistance. Furthermore, a markedly turbulent flow pattern was evidenced within the cerebral lesion. The presence of a cerebral arteriovenous malformation with an aneurysm of the vein of Galen was suggested and the provisional diagnosis was later confirmed by computed tomography and carotid angiography performed after birth.
Abstract: The purpose of this investigation was to analyze the changes in umbilical artery (UA) velocity waveforms after administration of nifedipine in 30 healthy pregnant women. The effects on fetal and maternal heart rates and maternal arterial pressure were also analyzed. The patients included in this double blind study received sublingually either 10 mg of nifedipine or a placebo. A transient fall of the UA resistance (as expressed by the pulsatility index) occurred 15 min after nifedipine administration, but resistance returned to control values after 90 min. Maternal heart rate increased after nifedipine administration and returned toward the control value by 45 min. Fetal heart rate and maternal mean arterial pressure did not change significantly. These data suggest a possible use of nifedipine to normalize the UA velocity waveform in pregnancies complicated by hypertension and fetal growth retardation.
Abstract: Seventy-five high-risk pregnancies were studied in order to define the clinical value of the analysis of fetal blood flow velocity waveforms in early screening for growth retardation. Recordings were obtained at 26-28 weeks' gestation, in the absence of ultrasonographic signs of growth retardation, using a pulsed duplex Doppler system. The pulsatility index was evaluated at the level of the umbilical artery, descending aorta, and internal carotid artery. Fetuses (N = 23) who developed growth retardation showed higher values of pulsatility index in the umbilical artery (P less than .001) and descending aorta (P less than .05) than fetuses of normal growth. In the internal carotid artery, the pulsatility index was lower (P less than .001) in the fetuses who developed growth retardation than in those with normal growth. The ratio between the pulsatility indexes of the umbilical and internal carotid arteries proved an accurate predictor of growth retardation (specificity 92.3%; sensitivity 78.2%; positive predictive value 81.8%; negative predictive value 90.5%; accuracy 88%).
Abstract: The pre-ejection period (PEP) of the cardiac cycle was measured in the human fetus using pulse Doppler in association with transabdominal ECG. The technique permitted the exact localization of the aortic valve, a good recording of its opening and the exact measurement of PEP. Between 32 and 42 weeks of pregnancy there is a strong correlation between PEP and gestational age. This new method seems to be an easy and reliable tool for measuring the PEP during intrauterine life.
Abstract: In order to verify whether fetal and maternal adrenal gland suppression induces effects on fetal behaviour, triamcinolone was administered to five healthy pregnant women at 35 weeks of gestation. Five patients of the same gestational age were used as control. Fetal heart rate (FHR) and fetal movements were recorded continuously over 2-h interval by means of cardiotocography. After 3 weeks (38 weeks of gestation) the recordings were repeated without drug administration. Cortisol, adrenocorticotropin hormone, 17 beta-estradiol and unconjugated estriol were measured at the same time every 2 h in maternal peripheral plasma. At 35 weeks we found a loss of circadian rhythms of the hormones investigated and modifications of ultradian and circadian patterns of FHR in the treated group with respect to the control. No differences in hormonal and biophysical parameters were found between the two groups after the end of treatment (38 weeks). These data suggest that the inhibition of fetal and maternal adrenal glands could cause modifications of FHR patterns.
Abstract: In order to evaluate the development of fetal behavioural states a longitudinal study was performed on 35 healthy fetuses during the last trimester of pregnancy. Fetal heart rate (FHR), gross fetal body movements (FM), fetal eye movements (FEM), fetal breathing movements (FBM) and micturition were simultaneously studied at two-week intervals from 28 weeks gestation onwards. Well-defined fetal behavioural states were observed only after 36 weeks gestation. Between 28 and 36 weeks the quiet-activity cycle of FHR was always detected and some fetal biophysical activities seemed to become related around this cycle.
Abstract: In the present investigation the effects of free fatty acids (FFA) and L-carnitine were investigated on the rat isolated uterine horn. The cumulative addition of FFA and L-carnitine to the isolated organ bath produced a significant increase of isometric developed tension and functional activity, especially evident at 5 mM carnitine concentration. No variations in the frequency of contractions were found. These data suggest a possible role of FFA as energy source in the rat uterus.
Abstract: In order to accurately detect the fetal behavioural state, we simultaneously measured fetal heart rate and multiple fetal activities in 27 healthy pregnant women at 38 to 40 weeks of gestation. We ultrasonically identified gross body movements, breathing movements and micturition. Analysis of fetal heart rate allowed us to distinguish two different patterns of fetal behaviour: active and quiet phases. The frequency distribution of the analysed fetal events was significantly different in these two phases. These data suggest that a complete biophysical profile of the fetus is effective in differentiating behavioural states and may improve the predictive accuracy of fetal heart rate analysis alone.
