Abstract: OBJECTIVES: To examine the clinical utility of the first-trimester biochemical markers of aneuploidy in their ability to predict subsequent delivery of a small-for-gestational age (SGA) infant. METHODS: We examined singleton pregnancies with no chromosomal abnormality and with complete outcome data that had undergone screening for trisomy 21 by a combination of fetal nuchal translucency (NT) thickness and maternal serum free beta-human chorionic gonadotropin (beta-hCG) and pregnancy-associated plasma protein-A (PAPP-A) at 11 + 0 and 13 + 6 weeks' gestation. The biochemical markers were converted to multiples of the expected normal median (MoM) for a pregnancy of the same gestation. The association between free beta-hCG and PAPP-A and the incidence of SGA were assessed by comparing the relative incidence at MoM cut-offs and birth-weight centile cut-offs. At various marker levels the likelihood ratios (LR) for SGA were also calculated after excluding other adverse pregnancy complications. RESULTS: There were 46,262 pregnancies resulting in live births with birth weight at or above the 10(th) centile, and 3,539 below the 10(th) centile for gestation (SGA). There was a significant inverse association between the risk for SGA and maternal serum PAPP-A MoM but not free beta-hCG MoM. At the 5(th) centile of the normal outcome group for PAPP-A (0.415 MoM) the odds ratios for SGA below the 10(th), 5(th) and 3(rd) centiles of normal were 2.70, 3.21 and 3.66 and the respective detection rates for SGA were 12.0%, 14.0% and 16.0%. CONCLUSIONS: Low levels of maternal serum PAPP-A are associated, in the absence of an abnormal karyotype, with an increased risk for subsequent delivery of an SGA infant.

Abstract: OBJECTIVES: To examine the clinical utility of the first-trimester markers of aneuploidy in their ability to predict preterm delivery. METHODS: We examined 54 722 singleton pregnancies with no chromosomal abnormality and with complete outcome data that had undergone screening for trisomy 21 by a combination of fetal nuchal translucency (NT) thickness and maternal serum free beta-human chorionic gonadotropin (beta-hCG) and pregnancy-associated plasma protein-A (PAPP-A) at 11 + 0 and 13 + 6 weeks' gestation. The biochemical markers were converted to multiples of the median (MoM) of the expected normal median for a pregnancy of the same gestation and the measurements of fetal NT were expressed as the difference (delta) from the normal median NT for crown-rump length. The association between free beta-hCG, PAPP-A and delta NT and the incidence of preterm delivery before 37 weeks or early preterm delivery before 34 weeks was assessed by comparing the relative incidence at a number of MoM or delta NT cut-offs and at various centile cut-offs. At various marker levels the likelihood ratios (LR) for preterm delivery and early preterm delivery were also calculated after excluding other adverse pregnancy complications. RESULTS: The risk of preterm delivery increased with decreasing maternal serum PAPP-A. In the 3132 cases delivering before 37 weeks the PAPP-A MoM was 0.91 and in the 1060 cases delivering before 34 weeks the PAPP-A MoM was 0.90. At the 5th centile of the normal outcome group for PAPP-A (0.415 MoM) the odds ratios for delivery before 37 weeks and before 34 weeks were 1.92 and 2.35, respectively. The respective values for the 5th centile of free beta-hCG (0.41 MoM) were 1.18 and 1.08 and for the 95th centile of delta NT they were 0.91 and 0.77, respectively. CONCLUSIONS: Low levels of maternal serum PAPP-A are associated, in the absence of an abnormal karyotype, with an increased risk of preterm or early preterm delivery. The LR profiles provided at various levels of PAPP-A may be of some help in counseling women with such results and may raise awareness among healthcare professionals for increased surveillance in such cases.

Abstract: BACKGROUND: ADAM12s is a placenta-derived glycoprotein that is involved in growth and differentiation, and has been shown to be a potential first-trimester and second-trimester marker of Trisomy 21 and other aneuploides. Maternal ADAM12s concentrations show a considerable temporal variation with gestational age and here we study the levels at 11-13 weeks of gestation to establish the effectiveness or otherwise at a time when other established markers are used. MATERIALS AND METHODS: Samples collected as part of routine first-trimester screening were retrieved from storage. In total, 46 samples from pregnancies with Trisomy 21 were identified and collected between 11 and 13 weeks of gestation-of these 83% had been identified by combined first-trimester screening. A series of 414 gestational age-matched samples collected during the same period formed the control group. ADAM12s was measured by a new DELFIA assay incorporating two monoclonals (6E6 and 8F8). Results were expressed as weight-corrected multiples of the median (MoM). RESULTS: The median MoM ADAM12s rose from 0.914 at 11 weeks to 1.032 at 13 weeks. CONCLUSIONS: Combining the data from this study and other published studies suggests that ADAM12s is unlikely to be of much additional value when screening for Trisomy 21 in the period 11-13 weeks. More studies are required looking at the potential of ADAM12s prior to 10 weeks.

Abstract: BACKGROUND: In a previous study, reduced levels of maternal serum placental protein 13 (PP13) in the first trimester have been correlated with adverse pregnancy outcomes. The objective of this study was to compare first-trimester PP13 levels in control pregnancies with pregnancies resulting in one or more of the following adverse outcomes: intrauterine growth restriction (IUGR), small and very small (3rd, 5th, 10th centile) for gestational age (SGA), low (<1.5 and < 2.5 kg) birth weight (LBW), macrosomia (the > 90th centile), large birth weight (>4.5 kg), preterm (35-36 weeks) and very early (<34 weeks) delivery (PTD), and intrauterine fetal demise (IUFD). METHODS: Maternal serum samples from 1940, 11 to 14 weeks singleton pregnancies, were assayed for PP13 and the concentrations were corrected for gestational age, maternal weight, smoking status, and ethnic origin. A comparison of the levels of PP13 in 364 controls and 1576 adverse outcome categories was made. PP13 levels were expressed in terms of both concentration and multiple of medians (MoMs). RESULTS: Comparison of PP13 MoMs from SGA, PTD, and low birth weight samples with control pregnancy samples showed no statistically significant difference. In macrosomic pregnancies (>90th centile), levels of PP13 were significantly higher than controls (p = 0.0263) although the number of cases in this study was small. CONCLUSION: Decreased levels of PP13 were not significantly correlated with the studied adverse pregnancy outcomes of IUGR, PTD low birth weight, and IUFD. Further studies are required to evaluate if measurement of PP13 has any value in the early assessment of pregnancies.

Abstract: BACKGROUND: Low levels of pregnancy associated plasma protein-A (PAPP-A) have been previously shown to be associated with pregnancies that subsequently develop pre-eclampsia. The objective of this study was to establish the relative risk for pre-eclampsia at various PAPP-A levels as an aid to counselling and follow up of pregnancies. METHODS: Maternal serum PAPP-A and free ss-human chorionic gonadotropin (ss-hCG) levels at 11 to 13 weeks of gestation from 224 singleton pregnancies that subsequently developed pre-eclampsia were compared to those from 47,770 normal singleton pregnancies resulting in live births after 37 weeks with birth weight greater than or equal to the 10th centile of normal for gestation. In all cases, the measured PAPP-A and free ss-hCG levels were expressed as multiple of the median (MoM). The association between metabolite levels and the incidence of pre-eclampsia was assessed by comparing the relative incidence at a number of MoM cut-offs and at various centiles. At various marker levels, the likelihood ratio for pre-eclampsia was also calculated. RESULTS: In the pre-eclampsia group the median PAPP-A MoM was significantly reduced (0.772 MoM, p < 0.0001) whilst the median free beta-hCG MoM was not different from controls (0.981 MoM, p = 0.26). With decreasing levels of PAPP-A, the likelihood ratio for pre-eclampsia increased. At the 5th centile of normal (PAPP-A MoM 0.415) the odds ratio was increased 4-fold and at this cut-off 15% of cases of pre-eclampsia would be identified. CONCLUSIONS: The graphical presentation of a likelihood ratio curve for pre-eclampsia at any PAPP-A MoM level is likely to be useful in counselling women with low levels of PAPP-A and a normal karyotype. Use of low levels of PAPP-A for selecting women for further follow-up with uterine artery Doppler may further improve the clinical discrimination.

Abstract: BACKGROUND: Here we study the levels of ADAM12s prior to and after 10 weeks of gestation to establish further the effectiveness or otherwise of ADAM12s as an early screening marker. MATERIALS AND METHODS: Samples collected as part of routine first-trimester screening were retrieved from storage at - 80 degrees C. In total, 55 samples from pregnancies with trisomy 21 were identified, 31 collected between the 6th and 9th weeks of gestation and 24 collected after the 10th week. A series of 567 gestational age-matched samples collected during the same period formed the control group. RESULTS: The median, multiples of the median (MoM) ADAM12s, at a median gestation of 10.0 weeks was 0.66, which was significantly lower than in the controls (p = < 0.001) when compared by Mann-Whitney test. The median MoM in those cases (n = 31) collected prior to 10 weeks was 0.618 MoM at a median gestation of 9.1 weeks. In those collected prior to 9 weeks (n = 14) the median was 0.596 at a median gestation of 8.6 weeks. CONCLUSIONS: The data from this study does not support data from a previous study showing ultra-low levels of ADAM12s in pregnancies affected by trisomy 21 prior to 10 weeks of gestation.

Abstract: OBJECTIVE: To examine whether maternal serum ADAM12s, a potential first- and second-trimester marker of fetal aneuploidy and fetal growth, had altered concentrations in the first or second trimester of pregnancies subsequently developing pre-eclampsia. METHODS: ADAM12s was measured by a time-resolved fluoroimmunoassay developed by PerkinElmer Life Science. Maternal serum samples from women taking part in early first-trimester aneuploidy screening in whom the pregnancy resulted in pre-eclampsia (64) were identified from a cohort of 4,390 singleton pregnancies in which uterine artery Doppler mean Pulsatility Index (PI) had been measured at 22-24 weeks. From amongst those cases delivering a normal term infant with birth weight greater than the 10th centile for gestational age 240 cases were selected as gestational age-matched controls. A second study group consisting of maternal serum taken at 22-24 weeks at the time of uterine artery Doppler in a group of 12 women developing pre-eclampsia were compared with 86 matched controls from a previously studied cohort of 24 cases and 144 controls. Serum ADAM12s concentrations were converted to multiple of the median (MoM) to take account of gestational age variation. RESULTS: First-trimester maternal serum ADAM12s levels in women who developed pre-eclampsia were reduced with a median MoM of 0.71 which was further reduced in those delivering prior to 35 weeks (0.50). At the 5th centile of normal (0.48 MoM) ADAM12s identified 27% of cases with pre-eclampsia and 47% of those with early pre-eclampsia. Combining ADAM12s with PAPP-A from a previous study only resulted in a further 1% increase in detection of all women developing pre-eclampsia. However combining ADAM12s with mean PI increased the detection rate to 66%. In the second trimester at 22-24 weeks the maternal serum ADAM12s levels were increased in those women developing pre-eclampsia compared to controls (709 vs 486 ug/L, p = 0.045). CONCLUSION: ADAM12s in addition to being a potential marker of aneuploidy may also be a marker of pre-eclampsia. Further studies are required to see if this can improve on the clinical discrimination already provided by PAPP-A in the early first trimester.

Abstract: BACKGROUND: ADAM12s (a disintegrin and metalloprotease) is a placenta-derived glycoprotein that is involved in growth and differentiation and has been shown to be a potential first-trimester and second-trimester marker of trisomy 21 and other aneuploides. Maternal ADAM12s concentrations show a considerable temporal variation with gestational age and in the initial study levels were found to be significantly reduced in the early first trimester. Here we study the levels prior to 10 weeks of gestation to establish further the effectiveness or otherwise of ADAM12s as an early screening marker. MATERIALS AND METHODS: Samples collected as part of routine first-trimester screening were retrieved from storage. In total, ten samples from singleton pregnancies with trisomy 21 were identified and were collected between the 8th and 9th weeks of gestation-of these 80% had been identified by combined first-trimester screening. A series of 62 gestational age-matched samples from singleton pregnancies collected during the same period formed the control group. ADAM12s was measured by a new DELFIA assay incorporating two monoclonals (6E6 and 8F8). Results were expressed as multiples of the median (MoM). RESULTS: The median MoM ADAM12s at a median gestation of 9.3 weeks was 0.61 which was significantly lower than in the controls (p = 0.011) when compared by the Mann-Whitney test. The corresponding median pregnancy associated plasma protein (PAPP-A) was 0.30 and free beta-human chorionic gonadotropin (beta-hCG) 2.02. CONCLUSIONS: Combining the data from this study and from the only other published study with data prior to 10 weeks suggests that ADAM12s may have the potential as an early screening marker for trisomy 21, but may not be as reduced as first thought.

Abstract: OBJECTIVES: To evaluate whether first-trimester levels of PAPP-A and serum free-beta-human chorionic gonadotrophin (free beta-hCG) vary with maternal blood group and rhesus status and to assess whether this has implications for first-trimester screening for chromosomal anomalies. METHODS: Blood group and rhesus status information was extracted from birth records for women undergoing first-trimester screening. The birth records were combined with prenatal screening records by an in-house developed record linkage software. In 2252 singleton pregnancies of normal obstetric outcome, the median weight-corrected, ethnicity-corrected and smoking-corrected MoM were compared in the various blood groups, using t-tests after log10 transformation of the marker MoM against the whole study group. RESULTS: Only those women with a B rhesus positive blood group had statistically significant higher MoM levels of PAPP-A (0.995 v 0.937). CONCLUSIONS: A larger study is required to establish the validity of this increase in PAPP-A in the B rhesus positive group. If this can be substantiated, the elevation in PAPP-A in this group may require correction when screening for chromosomal anomalies.

Abstract: OBJECTIVE: To evaluate whether measurement of maternal serum placental protein-13 (PP-13) and pregnancy-associated plasma protein-A (PAPP-A) at 11 + 0 to 13 + 6 weeks of gestation alone or in combination with second-trimester uterine artery pulsitility measured by Doppler velocimetry is useful in predicting those women who will develop pre-eclampsia METHODS: This was a nested case-control study of pre-eclampsia cases with controls matched for gestational age and storage time for the maternal serum. Samples were collected as part of a first-trimester prenatal chromosomal anomaly screening program and were routinely tested for PAPP-A. PP-13 was tested using an enzyme linked immunosorbent assay (ELISA) by an examiner who was blinded to pregnancy outcome. All patients also underwent uterine artery Doppler flow velocimetry to measure the mean pulsatility index (PI) at 22-24 weeks' gestation. RESULTS: There were 446 controls and 44 cases with early pre-eclampsia where delivery was induced prior to 35 weeks. In addition there were a further 44 cases with pre-eclampsia in which delivery was not induced before term. Median PP-13 levels for controls, all cases and early pre-eclampsia cases were 176.9, 121.9 and 111.7 pg/mL, with multiples of the median (MoMs) of 1.00, 0.69 and 0.63, respectively (P < 0.001). PAPP-A MoMs were 1.00, 0.89 (P = 0.076) and 0.89 (P = 0.042) and mean PIs were 1.0, 1.6 (P < 0.001) and 1.7 (P < 0.001) for controls, all cases and early cases, respectively. Receiver-operating characteristics (ROC) curve analysis for either all cases or early cases vs. controls yielded areas under the curve for PP-13, PAPP-A and PI respectively of 0.68 (95% CI, 0.61-0.74; P < 0.001), 0.56 (95% CI, 0.49-0.63; P = 0.076) and 0.79 (95% CI, 0.72-0.87; P < 0.001) for all cases and 0.71 (95% CI, 0.63-0.79; P < 0.001), 0.59 (95% CI, 0.51-0.68; P = 0.076) and 0.86 (95% CI, 0.77-0.94; P < 0.001) for early cases. At a specificity set to 0.80 the sensitivities were 0.50, 0.23 and 0.76 for PP-13, PAPP-A and PI in the early cases and 0.44, 0.24 and 0.73 in all cases. Combining PP-13 and PI using logistic regression analysis yielded an area under the curve of 0.84 (95% CI, 0.78-0.90; P < 0.001) and a sensitivity of 0.74 in all cases, and 0.90 (95% CI, 0.84-0.96; P < 0.001) and a sensitivity of 0.79 for early cases. PAPP-A with PI gave an area under the curve of 0.82 (95% CI, 0.76-0.90; P < 0.001) and a sensitivity of 0.76 in all cases. Combining PAPP-A with PP-13 and PI did not add significantly to the sensitivity. CONCLUSION: First-trimester PP-13 levels may be useful in predicting pre-eclampsia and early pre-eclampsia, and the accuracy of the method increases when coupled with second-trimester Doppler PI measurement. First-trimester PAPP-A provides some prediction for pre-eclamspia when combined with PI but does not add to the prediction of early pre-eclampsia when PP-13 and PI are used together. Further studies are required to establish the real value of PP-13 in first-trimester screening for pre-eclampsia.

Abstract: OBJECTIVE: To evaluate whether measurement of maternal serum PP13 at 22 to 24 weeks of gestation, alone or in combination with second-trimester biochemical markers or uterine artery pulsatility measured by Doppler velocimetry, is useful in predicting those women at risk of developing pre-eclampsia. STUDY DESIGN: A nested case-control study of pre-eclampsia cases with controls matched for gestational age and storage time for the maternal serum. PP13 was tested by an ELISA, with the samples blinded to pregnancy outcome. All patients also underwent uterine artery Doppler flow velocimetry at 22-24 weeks to measure the mean pulsatility index (PI). Results for Inhibin, Activin, PAPP-A and Free beta-hCG were available from previous studies. RESULTS: There were 73 controls and five cases with early pre-eclampsia in which delivery was induced prior to 35 weeks. In addition, there were a further seven cases with pre-eclampsia in which delivery was not induced before term. Median PP13 levels for controls and all cases were 295.9 and 212.6 pg/ml, and 171.2 pg/ml amongst the early pre-eclampsia cases, with the MoMs 1.00, 0.94 and 0.63, respectively (p < 0.001). Receiver operator characteristic (ROC) curve analysis for either all cases or early cases versus controls yielded areas under the curve of 0.588 (95% CI: 0.42-0.76; p = 0.1526) and 0.693 (0.47-0.92; p = 0.0441) for PP13. At a specificity set to 0.80, the sensitivity for PP13 in the early cases was 0.40 and that in all cases was 0.25. Combining PP13 bivariately with any of the markers (PI, PAPP-A, Activin, Inhibin or Free beta-hCG) tested in the 22-24 week period did not improve the detection of early, late or all cases of pre-eclampsia compared with either marker alone. CONCLUSION: Late second-trimester PP13 alone is unlikely to be useful in predicting pre-eclampsia and early pre-eclampsia, and its prediction does not increase when coupled with second-trimester Doppler PI or other potential biochemical markers. Measuring between-trimester temporal changes may be worthy of further investigation.

Abstract: BACKGROUND: ADAM12 (a disintegrin and metalloprotease 12) is a placentally derived glycoprotein that appears to be involved in growth and differentiation. The maternal serum concentration of ADAM12 appears to be a very good marker of trisomy 21 in the early first trimester when levels are reduced, and in the second trimester around 16-18 weeks levels are elevated. One small preliminary study of first trimester pregnancies with trisomy 18 found reduced levels in the maternal serum, and we examine herein the potential of ADAM12 as a marker of trisomy 18 in both the first and second trimester of pregnancy. MATERIALS AND METHODS: The concentration of ADAM12 was determined by a time-resolved immunofluorometric assay in 132 first and 12 second trimester cases of trisomy 18, and 389 first and 341 second trimester gestational age-matched control pregnancies. Medians of normal pregnancies were established by polynomial regression and used to determine the population distribution parameters for the trisomy 18 and control groups. Correlation with previously established pregnancy-associated plasma protein-A (PAPP-A) and free beta-human chorionic gonadotropin (beta-hCG) multiples of the median (MoMs) and nuchal translucency thickness (NT) MoM were determined and used to model the performance of first trimester screening with ADAM12 in combination with other first trimester markers. RESULTS: The maternal serum concentration of ADAM12 in the first trimester was significantly reduced with a median MoM of 0.829 (p < 0.001) and a mean log10 MoM SD of 0.2663 compared to 0.3353 in the controls. In the second trimester small series ADAM12 was significantly increased with a median MoM of 2.09 (p = 0.001) and a mean log10 MoM SD of 0.2607 compared to 0.4318 in controls. There was a significant correlation of ADAM12 MoM with gestational age (r = 0.510) in trisomy 18 cases, and the median MoM increased from 0.51 at 10 weeks to 1.28 at 13 weeks and 2.09 across the 14-18 week window. ADAM12 was correlated with PAPP-A (r = 0.1918) in the first trimester of cases with trisomy 18 but less so with NT (r = 0.1594) and free beta-hCG (r = 0.0938). Modeled detection rates incorporating ADAM12, free beta-hCG, and NT were 92% at 1% false positive rate (88% at 0.5%) A combination of all four markers had a detection rate of 96.5% at a false positive rate of 1% (95% at 0.5%). CONCLUSION: ADAM12 may be a useful addition to early screening for trisomy 18 alongside other chromosomal anomalies, particularly if biochemical screening can occur before 10 weeks.

Abstract: BACKGROUND: PAPP-A is a marker used as part of the most effective method of screening for chromosomal anomalies in the first trimester. ADAM12 is a recently discovered pregnancy associated member of the ADAM (a multidomain glycoprotein metalloprotease) family. Recently, ADAM12 has been shown as a potential marker for early screening for chromosomal anomalies. Both PAPP-A and ADAM12 have been identified as proteases to insulin-like growth factor binding proteins. In this role, they may have a regulatory function in controlling the amount of free bioactive insulin-like growth factor (IGF). We therefore wish to examine if the levels of either of these proteases are related to various growth related adverse pregnancy outcomes. MATERIALS AND METHODS: PAPP-A and ADAM12 were measured in a subset of samples collected at 11 to 14 weeks as part of an OSCAR clinic screening for chromosomal anomalies. Follow-up of pregnancies screened between September 1999 and August 2003 identified 1705 pregnancies with an outcome of intrauterine fetal demise on or after 24 weeks, preterm delivery at 24-34 weeks or 35-36 weeks, very low birthweight (<1.5 kg), low birthweight (<2.5 kg), large birthweight (>4.5 kg), and birth weight below the 3rd or 5th or 10th centile for gestation. A series of 414 normal outcome pregnancies constituted the control group.Marker levels were adjusted for gestation and maternal weight and the log MoM of the markers were compared using t-test of unequal variance between the control group and the various adverse outcome groups. RESULTS: ADAM12 and PAPP-A concentrations were reduced in low for gestational age birth weights and in all births with weights below 2.5 kg. There was a linear relationship between the severity of the IUGR and the decrease in PAPP-A and ADAM12. In the larger babies, only ADAM12 was found to be significantly increased in babies above the 90th centile of weight for gestation. CONCLUSIONS: The results of our study are compatible with the proposed role of ADAM12 and PAPP-A in promoting growth and development by breaking down IGF binding proteins and causing the release of free IGF for uptake into cells to promote growth. In those cases that eventually result in poor fetal growth, levels of PAPP-A and ADAM12 at 11-14 weeks are significantly lower than normal-in this instance, lowered PAPP-A and ADAM12 would result in less free IGF being available for cell uptake and growth stimulation. Further studies may elucidate if screening using such modalities can lead to new potential treatments for poorly growing fetuses.

Abstract: OBJECTIVE: To assess whether the maternal serum ADAM12s concentrations are altered in the first and second trimester of pregnancies complicated by rare aneuploides. METHODS: ADAM12s was measured by a semi-automated time-resolved immunofluorometric assay in a series of 60 first-trimester cases with trisomy 13, 78 first-trimester cases with Turner's syndrome, 38 first-trimester cases with triploidy and 24 first-trimester cases with sex aneuploidy-the cases were compared with the data from 389 first-trimester controls. In the second trimester, a smaller number of 6, 7, 2 and 13 cases, respectively, were compared with the data from 341 controls. All data were expressed as multiple of the median (MoM) and corrected for maternal weight. Correlation with previously analysed markers (PAPP-A, free beta-hCG and delta NT) was performed. RESULTS: The first-trimester median MoM ADAM12s was significantly lower than 1.0 in all types of rare aneuploidy with the possible exception of triploidy type II. A significant positive correlation with gestational age was reported for trisomy 13 and Turner's syndrome. ADAM12s was not significantly correlated with any other first-trimester marker. In the second trimester, ADAM12s values were marginally increased in these rare aneuploidies. CONCLUSIONS: ADAM12s has already been shown to be a possible early first- and second-trimester marker of trisomies 21 and 18. Our data also show the possibility of levels of this marker being altered in the first and second trimester of pregnancies with rare aneuploidies. This may be a useful addition to screening strategies in the future.

Abstract: BACKGROUND: ADAM 12 is a placenta-derived glycoprotein that is involved in growth and differentiation. The maternal serum concentration of ADAM 12 is a potential first-trimester maternal serum marker of Down syndrome (DS). Here we examine the potential of ADAM 12 as a second-trimester maternal serum marker of DS. MATERIALS AND METHODS: The concentration of ADAM 12 was determined in gestational week 14-19 in 88 DS pregnancies and 341 matched control pregnancies. Medians of normal pregnancies were established by polynomial regression and the distribution of log(10) MoM ADAM 12 values in DS pregnancies and controls determined. Correlations with alpha-fetoprotein (AFP) and free beta-human chorionic gonadotrophin (free beta-hCG) were established and used to model the performance of maternal serum screening with ADAM 12 in combination with other second-trimester serum markers. RESULTS: The ADAM 12 maternal serum concentration was significantly increased with a median MoM of 1.85 and a mean log(10) MoM (SD) of 0.268 (0.2678) compared to a mean log(10) MoM (SD) of 0.013 (0.4318) in controls. ADAM 12 correlated with maternal weight and ethnicity (with the serum concentration increased in Afro-Caribbeans), but neither with maternal age nor gestational age, and only marginally with AFP (r(DS) = 0.078, r(controls) = 0.093) and free beta-hCG (r(DS) = 0.073, r(controls) = 0.144. The increase in detection rate-for a false positive rate of 5%--by adding ADAM 12 to the double test (AFP + free beta-hCG) was 4%, similar to that of adding uE3 to the double test. CONCLUSION: ADAM 12 is an efficient second-trimester marker for DS. Further studies should be conducted to determine whether it may be a useful additional or alternative marker to those currently used in the second-trimester.

Abstract: BACKGROUND: A Disintegrin And Metalloprotease 12 (ADAM 12) is a glycoprotein synthesised by placenta and it has been shown to be a potential first-trimester maternal serum marker for Down syndrome (DS) in two small series. Here we analyse further, the potential of ADAM 12 as a marker for DS in a large collection of first-trimester serum samples. MATERIALS AND METHODS: The concentration of ADAM 12 was determined in 10-14-week pregnancy sera from 218 DS pregnancies and 389 gestational age-matched control pregnancies, which had been collected as part of routine prospective first-trimester screening programs (DS = 105) or as part of previous research studies (DS = 113). ADAM 12 was measured using a semi-automated time resolved immunofluorometric assay and median values for normal pregnancies were established by polynomial regression. These medians were then used to determine population distribution parameters for DS and normal pregnancy groups. Correlation with previously established PAPP-A and free beta-hCG multiple of the medians (MoMs) and delta nuchal translucency (NT) were determined and used to model the performance of first-trimester screening with ADAM 12 in combination with other first-trimester markers at various time periods across the first trimester. The benefits of a contingent testing model incorporating early measurement of PAPP-A and ADAM 12 were also explored. RESULTS: The maternal serum concentration of ADAM 12 was significantly reduced (p = 0.0049) with an overall median MoM of 0.79 in the DS cases and a log(10) MoM SD of 0.3734 in the DS cases and 0.3353 in the controls. There was a significant correlation of ADAM 12 MoM in DS cases with gestational age (r = 0.375) and the median MoM increased from 0.50 at 10-11 weeks to 1.38 at 13 weeks. ADAM 12 was correlated with maternal weight (r(controls) = 0.283), PAPP-A (r(controls) = 0.324, r(DS) = 0.251) but less so with free beta-hCG (r(controls) = 0.062, r(DS) = 0.049) and delta NT (r(controls) = 0.110, r(DS) = 0.151). ADAM 12 was significantly (p = 0.026) lower in smokers (0.87 vs 1.00) and elevated in Afro-Caribbean women compared to Caucasian women (1.34 vs 1.00).Population modelling using parameters from this and an earlier study showed that a combination of ADAM 12 and PAPP-A measured at 8-9 weeks and combined with NT and free beta-hCG measured at 12 weeks could achieve a detection rate of 97% at a 5% false-positive rate or 89% at a 1% false-positive rate. PAPP-A and ADAM 12 alone at 8-9 weeks could identify 91% of cases at a 5% false-positive rate. Using this as part of a contingent-screening model to select an intermediate risk group of women for NT and free beta-hCG at 11-12 weeks would enable the detection of 92% of cases with a 1% false-positive rate at a cost of providing NT and free beta-hCG for 6% of women with 94% of women having completed screening by the 10th week of pregnancy. CONCLUSION: ADAM 12 in early first trimester is a very efficient marker of DS. In combination with existing markers, it offers enhanced screening efficiency in a two-stage sequential first-trimester screening program or in a contingent-screening model, which may have benefits in health economies where universal access to high quality ultrasound is difficult. More data on early first-trimester cases with DS are required to establish more secure population parameters by which to assess further the validity of these models.

Abstract: OBJECTIVES: ADAM12-s is a placental protein. In early pregnancy, reduced maternal levels of ADAM12-s have been reported in association with foetal trisomy 21 or 18 and in cases that subsequently develop pre-eclampsia and foetal growth restriction. The aim of this study is to investigate the distribution of ADAM12-s in early pregnancy by comparing its concentration in maternal serum, amniotic fluid and coelomic fluid. METHODS: Coelomic fluid was obtained by coelocentesis from 13 singleton pregnancies with live foetuses at 6.9-9.3 weeks of gestation. Maternal serum was also obtained in all cases and in six cases amniotic fluid was also obtained. The concentration of ADAM12-s was measured by dissociation enhanced lanthanide fluoro-immunoassay. RESULTS: The median concentration of ADAM12-s in maternal serum was 132.7 (range 33.8-254.5) ng/mL and in coelomic fluid it was 10.5 (range 1.3-15.8) ng/mL; there were no detectable levels in five of the six amniotic fluid samples. The concentration of maternal serum ADAM12-s increased significantly with gestation (r = 0.862, p < 0.0001). There was no significant association between coelomic fluid ADAM12-s and either gestation (r = 0.255, p = 0.401) or maternal serum ADAM12-s (r = 0.302, p = 0.316). CONCLUSION: The distribution of ADAM12-s in maternal serum and the early embryonic fluid compartments is consistent with its syncytiotrophoblastic origin.

Abstract: OBJECTIVES: To examine the clinical utility of the first-trimester markers of aneuploidy in their ability to predict future fetal loss. METHODS: We examined 54,722 singleton pregnancies with no chromosomal abnormality and with complete outcome data that had undergone screening for trisomy 21 by a combination of fetal nuchal translucency (NT) thickness, maternal serum free beta-human chorionic gonadotropin (beta-hCG) and pregnancy-associated plasma protein-A (PAPP-A) at 11 + 0 and 13 + 6 weeks' gestation. The biochemical markers were converted to multiples of the expected normal median for a pregnancy of the same gestation (MoM) and the measurements of fetal NT were expressed as the difference (delta) from the normal median NT for crown-rump length (CRL). The association between free beta-hCG, PAPP-A and delta NT and the incidence of fetal loss prior to 24 weeks, at or after 24 weeks or at any time, was assessed by comparing the relative incidence at a number of MoM or delta NT cut-offs and at various centile cut-offs. At various marker levels the likelihood ratio (LR) for fetal loss was also calculated. RESULTS: The rate of fetal loss increased with decreasing maternal serum free beta-hCG and PAPP-A and increasing delta NT. At the 5th centile of the normal outcome group for free beta-hCG (0.41 MoM) the odds ratio for fetal loss before 24 weeks, at or above 24 weeks and at any gestation was 3.1, 1.8 and 2.6, respectively. The respective values for the 5th centile of PAPP-A (0.415 MoM) were 3.3, 1.9 and 2.8 and for the 95th centile of delta NT they were 2.5, 1.9 and 2.2, respectively. There was almost no correlation between reduced levels (<or=0.50 MoM) of PAPP-A and reduced levels of free beta-hCG in either the normal pregnancy group (r = 0.041) or the group with fetal death (r = 0.072), indicating relatively independent prediction by either biochemical marker. CONCLUSIONS: Low levels of maternal serum PAPP-A and free beta-hCG and increased fetal NT are associated, in the absence of an abnormal karyotype, with an increased risk of impending fetal death. The likelihood ratio profiles provided at various levels of PAPP-A or free beta-hCG may be of some help in counseling women with such results and raise awareness among health-care professionals for increased surveillance in such cases.

Abstract: OBJECTIVE: To evaluate a previous hypothesis that maternal serum biochemical markers used in the assessment of Down syndrome risk are related to maternal haemoglobin concentrations. METHODS: A series of 1306 second-trimester prenatal screening records were retrieved including information on marker levels (AFP and fbetahCG MoMs), Down's risk, a priori age risk, maternal weight and maternal height. Each individual record was merged with data from haematological investigations on samples collected on the same day. A similar series of 1688 first-trimester screening records were also retrieved including the maker levels for PAPP-A, and fbetahCG MoMs were merged with data from haematological investigations carried out on the same day. The two groups were categorised according to their haemoglobin levels; anaemic (less than 11.0 g/dL in first trimester and 10.5 g/dL in the second trimester), high haemoglobin (greater than 14.0 g/dL and 13.2 g/dL) or normal (between these ranges). An analysis was made of marker levels in the various groups before and after correction for ethnicity and of the screen-positive rate in the various groups. Using a formula based on maternal height and weight, variation of marker levels with plasma volume was assessed. RESULTS: In the first trimester, 12.6% of the pregnant population was anaemic and 1.6% had elevated haemoglobin levels. In the second trimester this was 12.7 and 3.9%. These figures varied considerably with ethnic origin, with Asian and Afro-Caribbean women being more anaemic than Caucasian women. Haemoglobin levels declined by 7% between the 11- and 21-week period. Maternal plasma volume (as calculated by a widely used maternal height and weight relationship) was not correlated with weight-corrected biochemical marker MoMs in either trimester. A weak but significant correlation of maternal plasma volume and haemoglobin concentration was observed. There was no significant correlation between biochemical marker MoMs and haemoglobin concentration. Although the proportion of pregnancies designated screen positive decreased as haemoglobin levels increased, this was paralleled by a decrease in the maternal age a priori risk. CONCLUSIONS: There is no relationship between maternal haemoglobin levels and the levels of Down syndrome markers in either the first or second trimester. Biochemical marker levels do not need to be corrected for haemoglobin concentrations when used in screening for Down syndrome.

Abstract: BACKGROUND: Previous studies have shown an association between low first trimester maternal serum free beta-hCG and PAPP-A and subsequent development of pregnancy complications. Similarly, uterine artery Doppler in the late second trimester has shown that high impedance to flow is associated with increased risk for preeclampsia and fetal growth restriction. The objective of this study is to determine whether there is an association between the maternal serum concentration of PAPP-A and free beta-hCG at 11-13(+6) weeks with the uterine artery pulsatility index (PI) at 22-24 weeks, and secondly, to compare the screening characteristics of the two methods in the prediction of adverse pregnancy outcome. METHODS: Maternal serum PAPP-A and free beta-hCG at 11-13(+6) weeks and uterine artery PI at 22-24 weeks were measured in 4390 women with singleton pregnancies. Pregnancies with chromosomal defects or fetal anomalies were excluded. The biochemical and Doppler measurements were compared between those with normal outcome and those resulting in spontaneous preterm delivery, pre-eclampsia and fetal growth restriction (FGR). Detection rates using a combination of the biochemical and Doppler measurements were investigated. RESULTS: In the pregnancies resulting in pre-eclampsia (n = 64) and FGR (n = 172), the median PAPP-A was lower (0.844 and 0.813 MoM), the median uterine artery mean PI was higher (1.56 and 1.18) but the median free betahCG was not significantly different (0.923 and 0.933 MoM) than in the normal outcome group. In the preterm delivery group (n = 159), the median free beta-hCG (0.944 MoM) and uterine artery mean PI (1.06) were not significantly different from normal but the median PAPP-A (0.928 MoM) was significantly lower than normal. In screening for pre-eclampsia, the detection rate, for a 5% false-positive rate, was 14.1% for PAPP-A, 54.7% for uterine artery mean PI and 62.1% for a combination of PAPP-A and uterine artery mean PI. CONCLUSION: Maternal serum PAPP-A at 11-13(+6) of gestation is significantly lower in adverse pregnancy outcomes. The combination of first trimester serum PAPP-A and uterine artery mean PI at 22-24 weeks improves the screening efficacy for the prediction of pre-eclampsia.