First-trimester maternal serum PAPP-A and free-beta subunit human chorionic gonadotropin concentrations and nuchal translucency are associated with obstetric complications: a population-based screening study (the FASTER Trial)

PP13 mRNA expression in trophoblasts from preeclamptic placentas

To assess the role of placental protein 13 (PP13) in the pathogenesis of preeclampsia, the messenger RNA expression of PP13 was investigated in the trophoblasts from first and third trimester placenta. First, syncytiotrophoblasts and extravillous trophoblasts were separated from frozen section of third trimester placenta obtained from pregnant women with and without preeclampsia by laser microdissection. The PP13 levels of syncytiotrophoblasts were significantly higher than those of extravillous trophoblasts. The expression levels in syncytiotrophoblasts from the preeclampsia were significantly lower than those from normal. Next, the PP13 expression was assessed in trophoblasts from residual samples of chorionic villus sampling at 11 weeks of gestation, who subsequently developed preeclampsia. The levels in the preeclampsia group were significantly lower than those of normal cases. These findings indicate that an alteration in the PP13-messenger RNA expression in the trophoblasts may be associated with the pathogenesis of preeclampsia.

Down syndrome biochemical markers and screening for preeclampsia at first and second trimester: correlation with the week of onset and the severity

OBJECTIVES

To estimate the combined screening performance of first and early second trimester prenatal serum markers for Down syndrome, in screening for the development of preeclampsia, and analyze the correlation among marker levels, week of onset, and severity of the disease.

METHODS

A retrospective cohort study was carried out on 32 women with preeclampsia and 3044 controls. Serum samples from these pregnancies were assayed for pregnancy-associated plasma protein-A (PAPP-A), alpha-fetoprotein (AFP), unconjugated estriol (uE3), human chorionic gonadotrophin (hCG), and inhibin-A. A likelihood ratio and the odds of being affected given a positive result (OAPR) of various combinations of markers were calculated and receiver operating characteristic (ROC) curves analysis was performed.

RESULTS

In the pregnancies that subsequently developed preeclampsia, first trimester PAPP-A concentration was significantly lower and concentrations of early second trimester inhibin-A and hCG significantly elevated. Levels of early second trimester uE3 and AFP were not significantly altered. We also found that inhibin-A correlates with both onset of the disease and the severity.

CONCLUSION

Down syndrome biochemical markers levels are altered in those patients who subsequently developed preeclampsia and may be a useful screening test for preeclampsia. Inhibin-A is the most predictive marker and correlates with the severity of subsequent preeclampsia and inversely with the week of occurrence of preeclampsia.

Prediction of patient-specific risk for fetal loss using maternal characteristics and first- and second-trimester maternal serum Down syndrome markers

OBJECTIVE

To develop and evaluate a method of estimating patient-specific risk for fetal loss by combining maternal characteristics with serum markers.

STUDY DESIGN

Data were obtained on 36,014 women from the FaSTER trial. Separate likelihood ratios were estimated for significant maternal characteristics and serum markers. Patient-specific risk was calculated by multiplying the incidence of fetal loss by the likelihood ratios for each maternal characteristic and for different serum marker combinations.

RESULTS

Three hundred eighteen women had fetal loss < 24 weeks (early) and 103 > 24 weeks (late). Clinical characteristics evaluated included maternal age, body mass index, race, parity, threatened abortion, previous preterm delivery, and previous early loss. Serum markers studied as possible predictors of early loss included first-trimester pregnancy-associated plasma protein A and second-trimester alpha-fetoprotein, and unconjugated estriol. A risk assessment for early loss based on all of these factors yielded a 46% detection rate, for a fixed 10% false-positive rate, 39% for 5% and 28% for 1%. The only significant marker for late loss was inhibin A. The detection rate was 27% for a fixed 10% false-positive rate and only increased slightly when clinical characteristics were added to the model.

CONCLUSION

Patient-specific risk assessment for early fetal loss using serum markers, with or without maternal characteristics, has a moderately high detection. Patient-specific risk assessment for late fetal loss has low detection rates.

Serum screening with Down's syndrome markers to predict pre-eclampsia and small for gestational age: systematic review and meta-analysis

Background

Reliable antenatal identification of pre-eclampsia and small for gestational age is crucial to judicious allocation of monitoring resources and use of preventative treatment with the prospect of improving maternal/perinatal outcome. The purpose of this systematic review was to determine the accuracy of five serum analytes used in Down's serum screening for prediction of pre-eclampsia and/or small for gestational age.

Methods

The data sources included Medline, Embase, Cochrane library, Medion (inception to February 2007), hand searching of relevant journals, reference list checking of included articles, contact with experts. Two reviewers independently selected the articles in which the accuracy of an analyte used in Downs's serum screening before the 25^th gestational week was associated with the occurrence of pre-eclampsia and/or small for gestational age without language restrictions. Two authors independently extracted data on study characteristics, quality and results.

Results

Five serum screening markers were evaluated. 44 studies, testing 169,637 pregnant women (4376 pre-eclampsia cases) and 86 studies, testing 382,005 women (20,339 fetal growth restriction cases) met the selection criteria. The results showed low predictive accuracy overall. For pre-eclampsia the best predictor was inhibin A>2.79MoM positive likelihood ratio 19.52 (8.33,45.79) and negative likelihood ratio 0.30 (0.13,0.68) (single study). For small for gestational age it was AFP>2.0MoM to predict birth weight < 10^th centile with birth < 37 weeks positive likelihood ratio 27.96 (8.02,97.48) and negative likelihood ratio 0.78 (0.55,1.11) (single study). A potential clinical application using aspirin as a treatment is given as an example.

There were methodological and reporting limitations in the included studies thus studies were heterogeneous giving pooled results with wide confidence intervals.

Conclusion

Down's serum screening analytes have low predictive accuracy for pre-eclampsia and small for gestational age. They may be a useful means of risk assessment or of use in prediction when combined with other tests.

Individualized norms of optimal fetal growth: fetal growth potential

OBJECTIVE

To demonstrate that individualized optimal fetal growth norms, accounting for physiologic and pathologic determinants of fetal growth, better identify normal and abnormal outcomes of pregnancy than existing methods.

METHODS

In a prospective cohort of 38,033 singleton pregnancies, we identified 9,818 women with a completely normal outcome of pregnancy and characterized the physiologic factors affecting birth weight using multivariable regression. We used those physiologic factors to individually predict optimal growth trajectory and its variation, growth potential, for each fetus in the entire cohort. By comparing actual birth weight with growth potential, population, ultrasound, and customized norms, we calculated for each fetus achieved percentiles, by each norm. We then compared proportions of pregnancies classified as normally grown, between 10th and 90th percentile, or aberrantly grown, outside this interval, by growth potential and traditional norms, in 14,229 complicated pregnancies, 1,518 pregnancies with diabetes or hypertensive disorders, and 1,347 pregnancies with neonatal complications.

RESULTS

Nineteen physiologic factors, associated with maternal characteristics and early placental function, were identified. Growth potential norms correctly classified significantly more pregnancies than population, ultrasound, or customized norms in complicated pregnancies (26.4% compared with 18.3%, 18.7%, 22.8%, respectively, all P<.05), pregnancies with diabetes or hypertensive disorders (37.3% compared with 23.0%, 28.0%, 34.0%, respectively, all P<.05) and neonatal complications (33.3% compared with 19.7%, 24.9%, 29.8%, respectively, all P<.05).

CONCLUSION

Growth potential norms based on the physiologic determinants of birth weight are a better discriminator of aberrations of fetal growth than traditional norms.

LEVEL OF EVIDENCE

II.

First-trimester maternal placental protein 13 levels in pregnancies resulting in adverse outcomes

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.

First-trimester pregnancy-associated plasma protein A and subsequent abnormalities of fetal growth

OBJECTIVE

The purpose of this study was to describe the relationship between first-trimester pregnancy-associated plasma protein A (PAPP-A) and birthweight along its continuum and at its extremes.

STUDY DESIGN

This was a retrospective cohort of 1371 women who underwent first-trimester screening for fetal aneuploidy and who delivered at our hospital.

RESULTS

First-trimester PAPP-A has a positive relationship with birthweight. As PAPP-A decreases, the risk of small-for-gestational-age (SGA) infants increases. PAPP-A of <10%, <5%, and <1% were associated with an increasing adjusted odds ratio for SGA infants (2.0 [95% CI, 1.2-3.5; P = .012]; 2.4 [95% CI, 1.2-4.7; P = .015]; 9.3 [95% CI, 3.4-25.5; P = .001], respectively). PAPP-A levels of >90% were associated with an adjusted odds ratio for birthweight of >4500 g of 2.9 (95% CI, 1.02-8.17; P = 0.046).

CONCLUSION

First-trimester PAPP-A is a marker of placental function that correlates with birthweight along its continuum and at its extremes. The strong association between low PAPP-A and SGA warrants further investigation of its usefulness as a screening tool.

First-trimester ultrasound and biochemical markers of aneuploidy and the prediction of preterm or early preterm delivery

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.

First-trimester biochemical markers of aneuploidy and the prediction of small-for-gestational age fetuses

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.

Stillbirth

In the UK, about one in 200 infants is stillborn, and rates of stillbirth have recently slightly increased. This recent rise might reflect increasing frequency of some important maternal risk factors for stillbirth, including nulliparity, advanced age, and obesity. Most stillbirths are related to placental dysfunction, which in many women is evident from the first half of pregnancy and is associated with fetal growth restriction. There is no effective screening test that has clearly shown a reduction in stillbirth rates in the general population. However, assessments of novel screening methods have generally failed to distinguish between effective identification of high-risk women and successful intervention for such women. Future research into stillbirth will probably focus on understanding the pathophysiology of impaired placentation to establish screening tests for stillbirth, and assessment of interventions to prevent stillbirth in women who screen positive.

PAPP-A levels as an early marker of idiopathic preterm birth: a pilot study

OBJECTIVE

To evaluate late PAPP-A levels as predictive of preterm birth in symptomatic women.

STUDY DESIGN

Prospective cohort study of singleton gestations, 23 to 34 weeks, and symptoms of preterm labor. PAPP-A, IGF-I and IGF-III analysis were performed. Primary end point was delivery < or =7 days. Accuracy and optimally predictive PAPP-A values were based on receiver operator characteristic (ROC) curves.

RESULT

In all, 26 women (51%) delivered < or =7 days post-admission (Group 1); 25 women (49%) >7 days (Group 2). Group 1 mean PAPP-A=38 000 vs 55 333 for Group 2 (P<0.04). Group 1 mean gestational age at delivery=29 weeks vs 37 weeks for Group 2 (P<0.00014). PAPP-A level < or =30,000 mU l(-1) had highest specificity (88%), sensitivity (50%), and positive predictive (81%) and negative predictive (62%) values for delivery < or =7 days. ROC area under curve=0.703.

CONCLUSION

PAPP-A levels < or =30,000 mU l(-1) at admission was associated with increased risk for preterm birth < or =7 days, supporting active management and therapeutic approach in these women.

Prediction and Prevention of Recurrent Spontaneous Preterm Birth

Rates of preterm birth have continued to rise despite intensive research efforts over the last several decades. A woman who has a spontaneous preterm birth is at high risk for a subsequent preterm birth. Studies have identified clinical, sonographic, and biochemical markers that help to identify the women at highest risk. Determining cervical length and measuring cervicovaginal fibronectin have been proposed as useful tools for evaluating women at risk of preterm birth and may identify those who might benefit from a timely course of antenatal corticosteroids, but effective interventions to prevent preterm birth remain elusive. In the prevention of recurrent spontaneous preterm birth, recent trials have confirmed the use of progesterone beginning in the second trimester as an effective intervention. Optimal management of women with a history of spontaneous preterm birth includes a thorough review of the obstetric, medical, and social history, with attention to potentially reversible causes of preterm birth (eg, smoking cessation, acute infections, strenuous activities), accurate ultrasound dating, consideration of progesterone therapy beginning at 16-20 weeks of gestation, and close surveillance during the pregnancy for evolving findings. Results from the ongoing trials of cerclage as an interventional therapy and omega-3 fatty acid supplementation as a preventive therapy will provide additional knowledge for the optimal management of these high-risk women.

First-trimester placental protein 13 screening for preeclampsia and intrauterine growth restriction

OBJECTIVE

The purpose of this study was to evaluate first-trimester serum placental protein 13 (PP13) as a screening test for preeclampsia and intrauterine growth restriction (IUGR).

STUDY DESIGN

We performed a prospective, nested case-control study in the Massachusetts General Hospital Obstetric Maternal Study. PP13 was measured by solid-phase sandwich enzyme-linked immunosorbent assay in serum samples that were collected at the first prenatal visit (9-12 weeks of gestation) from women who subsequently experienced preeclampsia (n = 47), IUGR (n = 42), or preterm delivery (n = 46). Women with uncomplicated term deliveries served as control subjects (n = 290) and were matched to cases by gestational age when serum was collected and for the duration of specimen storage.

RESULTS

The median first-trimester PP13 level was 132.5 pg/mL in the control subjects. Median PP13 levels were significantly lower among women who had preeclampsia (27.2 pg/mL; P < .001), IUGR (86.6 pg/mL; P < .001), and preterm delivery (84.9 pg/mL; P = .007). When PP13 was expressed as multiples of the gestational age-specific medians among the control subjects, the multiples of the medians were 0.2 for preeclampsia, 0.6 for IUGR, and 0.6 for preterm delivery (P < .001 for each disorder compared with control subjects). Receiver operating characteristic analysis yielded areas under the curve of 0.91, 0.65, and 0.60 for preeclampsia, IUGR, and preterm delivery, respectively. At a 90% specificity rate, the corresponding sensitivities were 79%, 33%, and 28%, respectively.

CONCLUSION

The screening of maternal PP13 levels in the first trimester is a promising diagnostic tool for the prediction of preeclampsia with high sensitivity and specificity.

First-trimester ADAM12 and PAPP-A as markers for intrauterine fetal growth restriction through their roles in the insulin-like growth factor system

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.

Nuchal Translucency and First Trimester Risk Assessment

First-trimester risk assessment for fetal aneuploidy using nuchal translucency (NT) measurement is rapidly gaining popularity in the United States. In combination with maternal serum markers in the first trimester, the screening performance is exceptionally good, with detection rates of more than 80% at a screen positive rate of 5%. Recently, the method has been validated for screening for Down syndrome and other aneuploidies in multicenter trials in the United States and elsewhere. Compliance with established criteria for measurement of the NT is essential to achieve uniform reliability and high screening test sensitivity. There is an international consensus about the importance of specific training in the NT examination, conformity to standards of NT measurement, and regular audit for quality assurance. In the United States, the Nuchal Translucency Quality Review program has been developed to administer credentialing and quality review for registered practitioners. The Nuchal Translucency Quality Review credentials signify the proficiency of the sonographer or sonologist in NT measurement and participation in a regular quality assurance audit. We encourage accreditation of clinical sites offering first-trimester risk assessment to ensure the highest quality care.

Screening for aneuploidy in first and second trimesters: is there an optimal paradigm?

PURPOSE OF REVIEW

This review serves to explore the recent literature regarding aneuploidy screening in both first and second trimesters. We aim to construct a comparative analysis of a range of proposed strategies for screening for trisomy 21.

RECENT FINDINGS

First trimester combined screening (sonographic nuchal translucency combined with serum markers pregnancy-associated plasma protein A and the free beta subunit of human chorionic gonadotrophin) has superseded second trimester serum screening (alpha-fetoprotein, total human chorionic gonadotrophin, unconjugated estriol with or without inhibin-A) as a screening paradigm for the detection of trisomy 21. This move is attributed to the recognition of superior detection rates, lower false-positive rates and earlier results associated with the former strategy. Septated cystic hygroma has been recognized as a distinct entity which confers a high risk of aneuploidy and structural malformations. Further advances in screening performance are achievable by combining the results of first and second-trimester screens in a sequential manner, with much interest generated by programs that only include second-trimester testing contingent upon first-trimester results.

SUMMARY

Screening strategies for aneuploidy continue to evolve, with the most recent evidence favouring a contingent sequential approach.

Association between birth weight and first-trimester free beta-human chorionic gonadotropin and pregnancy-associated plasma protein A

STUDY OBJECTIVE

To assess the relationship between first-trimester maternal serum PAPP-A and free beta-hCG and birth weight.

DESIGN

Observational study.

SETTING

Teaching hospital.

PATIENT(S)

Singleton pregnancies (n = 1,630) at 10-14 weeks of gestation.

INTERVENTION(S)

Fluorimetric immunoassays for maternal serum pregnancy-associated plasma protein A (PAPP-A) and free beta-hCG.

MAIN OUTCOME MEASURE(S)

Customized birth weight percentiles, calculated taking into account maternal height, weight, ethnic origin, parity, smoking status, and fetal gender.

RESULT(S)

There was a significant positive correlation between birth weight and PAPP-A, but not free beta-hCG levels. Maternal serum levels of PAPP-A were significantly lower in small-for-gestation (SGA) newborns than in control subjects and were significantly higher in large-for-gestation (LGA) newborns than in control subjects. Maternal serum free beta-hCG levels were lower in pregnancies complicated by pre-eclampsia than in normotensive ones. Multivariable analysis found PAPP-A to be an independent predictor of absolute birth weight, SGA, and LGA. Free beta-hCG was found to be an independent predictor of gestational hypertension and pre-eclampsia. Neither of the two markers was associated with preterm delivery.

CONCLUSION(S)

Maternal serum PAPP-A levels in the late first trimester of pregnancy are associated with subsequent fetal growth (including both physiologic variation and abnormal growth), and decreased free beta-hCG is more predictive of hypertensive disorders of pregnancy.

Nuchal translucency as a predictor of adverse pregnancy outcome

BACKGROUND

Thickened nuchal translucency (NT) has been related to fetal genetic syndromes, structural abnormalities, and other diseases. The aim of this research was to evaluate the association of NT with adverse pregnancy outcomes.

STUDY DESIGN

In the period 2002-2004 in 2104 pregnant women between 10+6 and 13+5 weeks' gestation, NT was evaluated as a parameter for aneuploidy screening: out of these, 734 singleton pregnant women that underwent 2nd trimester amniocentesis and whose pregnancy outcome were known were selected. NT was statistically correlated to pregnancy and neonatal outcome.

RESULTS

Median gestational age (GA) at NT evaluation was 11+2 weeks' gestation. NT median was 1.1 mm (0.9-1.4 mm, 25th-75th centile, range 0.5-4.0 mm). After multiple logistic regressions, the variables significantly associated to NT values were: threatened preterm labor (p<0.008) and preterm labor (p<0.02). The best diagnostic accuracy point was NT>95th centile and >1.5 MoM for the prediction of threatened preterm labor.

CONCLUSION

In this series, increased NT values were associated to threatened preterm labor and preterm labor in euploid fetuses: this finding may have clinical consequences in the management of such pregnancies.

Uterine artery Doppler in the prediction of adverse pregnancy outcome

PURPOSE OF REVIEW

To review publications, published during the past year, that have examined uterine artery Doppler findings in women with adverse pregnancy outcome.

RECENT FINDINGS

Almost two-thirds of stillbirths that occur in the early preterm period (up to 32 weeks) can be predicted by uterine artery Doppler at 23 weeks. First trimester screening studies have shown that an abnormal result increases the risk of subsequent fetal growth restriction, and such women are at particularly high risk when indices remain abnormal in the second trimester. Studies combining uterine artery Doppler with maternal serum markers have demonstrated that measurement of first-trimester maternal serum pregnancy-associated plasma protein A and free beta human chorionic gonadotrophin improve sensitivities of second-trimester Doppler. As these are frequently measured in Down syndrome screening and they lend themselves in screening for pre-eclampsia. Women with abnormal first and second-trimester serum markers constitute a high-risk group. Maternal serum placental protein 13 remains a promising method for early screening, although a recent study suggests lower sensitivities than initially reported.

SUMMARY

Uterine artery Doppler screening identifies women at high risk for developing adverse pregnancy outcomes. Detection rates may be increased and false positive rates reduced by combination with maternal characteristics or serum markers.

Screening for pre-eclampsia and fetal growth restriction by uterine artery Doppler and PAPP-A at 11-14 weeks' gestation

OBJECTIVE

To assess the role of maternal demographic characteristics, uterine artery Doppler velocimetry, maternal serum pregnancy-associated plasma protein-A (PAPP-A) and their combination in screening for pre-eclampsia and small-for-gestational age (SGA) fetuses at 11-14 weeks.

METHODS

This was a prospective study of 878 consecutive women presenting for a routine prenatal ultrasound examination at 11-14 weeks. Pulsed wave Doppler was then used to obtain uterine artery flow velocity waveforms and the mean pulsatility index (PI) of the uterine arteries was calculated. Maternal serum samples for PAPP-A were assayed. Along with maternal history, these measurements were compared in their ability to predict adverse outcome, defined as pre-eclampsia and/or SGA and/or placental abruption.

RESULTS

Mean uterine artery PI > or = 95(th) centile and PAPP-A < or = 10(th) centile each predicted 23% of the women that developed pre-eclampsia and 43% of cases of placental abruption. For SGA < or = 5(th) centile, mean uterine artery PI > or = 95(th) centile predicted 23% of cases and PAPP-A < or = 10(th) centile predicted 34%. Independent predictors for subsequent development of pre-eclampsia were increased mean uterine artery PI > or = 95(th) centile (OR, 2.76; 95% CI, 1.11-6.81) and maternal history of pre-eclampsia/hypertension (OR, 50.54; 95% CI, 10.52-242.73). The predicting factors for SGA < or = 5(th) centile were increased mean uterine artery PI > or = 95(th) centile (OR, 2.0; 95% CI, 1.07-3.74) and low PAPP-A (OR, 0.43; 95% CI, 0.20-0.93). Increased uterine artery PI was the only independent factor in the prediction of placental abruption (OR, 8.49; 95% CI, 2.78-25.94). The combination of uterine artery PI and maternal history of pre-eclampsia/hypertension was better than was using uterine artery Doppler alone in predicting pre-eclampsia. Similarly, for the prediction of SGA < or = 5(th) centile, combining uterine artery Doppler and maternal serum PAPP-A was better than was uterine artery Doppler alone. In both cases, the difference approached statistical significance.

CONCLUSIONS

The combination of maternal history with abnormal uterine artery Doppler and low PAPP-A level at 11-14 weeks achieves better results than does either test alone in the prediction of pre-eclampsia and SGA.

Placental abruption

Placental abruption complicates about 1% of pregnancies and is a leading cause of vaginal bleeding in the latter half of pregnancy. It is also an important cause of perinatal mortality and morbidity. The maternal effect of abruption depends primarily on its severity, whereas its effect on the fetus is determined both by its severity and the gestational age at which it occurs. Risk factors for abruption include prior abruption, smoking, trauma, cocaine use, multifetal gestation, hypertension, preeclampsia, thrombophilias, advanced maternal age, preterm premature rupture of the membranes, intrauterine infections, and hydramnios. Abruption involving more than 50% of the placenta is frequently associated with fetal death. The diagnosis of abruption is a clinical one, and ultrasonography and the Kleihauer-Betke test are of limited value. The management of abruption should be individualized on a case-by-case basis depending on the severity of the abruption and the gestational age at which it occurs. In cases where fetal demise has occurred, vaginal delivery is preferable. Disseminated intravascular coagulopathy should be managed aggressively. When abruption occurs at or near term and maternal and fetal status are reassuring, conservative management with the goal of vaginal delivery may be reasonable. However, in the presence of fetal or maternal compromise, prompt delivery by cesarean is often indicated. Similarly, abruption at extremely preterm gestations may be managed conservatively in selected stable cases, with close monitoring and rapid delivery should deterioration occur. Most cases of placental abruption cannot be predicted or prevented. However, in some cases, maternal and infant outcomes can be optimized through attention to the risks and benefits of conservative management, ongoing evaluation of fetal and maternal well-being, and through expeditious delivery where appropriate.

First-trimester ultrasound and biochemical markers of aneuploidy and the prediction of impending fetal death

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.

Correlation between first-trimester uterine artery Doppler indices and maternal serum free β-human chorionic gonadotropin and pregnancy-associated plasma protein A

OBJECTIVE

To assess the correlation between first-trimester uterine artery Doppler measurements and maternal serum levels of free beta-hCG and pregnancy-associated plasma protein A (PAPP-A).

DESIGN

Observational study.

SETTING

Teaching hospital.

PATIENT(S)

Four hundred thirty-three women at 10-14 weeks of gestation.

INTERVENTION(S)

Doppler ultrasound of the uterine arteries. Fluorimetric immunoassays for free beta-hCG and PAPP-A.

MAIN OUTCOME MEASURE(S)

Uterine artery mean resistance index (RI), pulsatility index (PI), and number of early diastolic notches. Maternal serum levels of free beta-hCG and PAPP-A.

RESULT(S)

There were 401 uncomplicated pregnancies. In this group, free beta-hCG and PAPP-A did not significantly correlate with uterine artery RI or PI (r values between -0.089 and 0.029, all nonsignificant). Free beta-hCG and PAPP-A levels did not significantly change with the number of notches. Uterine artery resistance and PAPP-A levels were independently correlated with birth weight.

CONCLUSION(S)

Preliminary evidence suggests that first-trimester uterine artery Doppler measurements do not correlate with maternal serum levels of free beta-hCG and PAPP-A. This may allow their combined use in multivariate screening for pregnancy complications.

The efficacy of first-trimester PAPP-A and free beta hCG levels for predicting adverse pregnancy outcome

OBJECTIVE

To determine whether first-trimester measurements of maternal serum PAPP-A and free beta hCG levels were associated with adverse pregnancy outcomes.

STUDY DESIGN

First trimester maternal serum free beta hCG and PAPP-A were measured in 490 singleton pregnancies. Pregnancies were followed by the fetal-maternal unit, and predictive efficacy of these markers for small for gestational age (SGA) babies, gestational diabetes mellitus and hypertensive disorders were analyzed by cut-off values determined by using a ROC analysis, and also, by using the fifth percentile as the cut-off value.

RESULTS

The sensitivities for PAPP-A in predicting pregnancies with a SGA baby and those complicated by a hypertensive disorder were 49% and 73%, respectively, when optimal cut-off values were used. Specificities were 76% and 65%, respectively. Serum free beta hCG had no predictive value for individual pregnancy outcomes.

CONCLUSION

Efficacy of first trimester maternal serum markers in predicting adverse pregnancy outcome is low. Even after optimization of cut-off values, these markers do not appear to be clinically acceptable as an effective tool for screening for adverse pregnancy outcomes.

Correlation between first trimester fetal bone length and maternal serum pregnancy-associated plasma protein-A (PAPP-A)

BACKGROUND

Pregnancy-associated plasma protein-A (PAPP-A) is produced by the embryo and placenta during pregnancy, and its maternal serum concentrations are related to subsequent fetal growth. Evidence from animal models and in vitro experiments suggests that PAPP-A is particularly involved in the regulation of bone development. The aim of this study was to assess the correlation between late first trimester fetal bone length and maternal serum levels of PAPP-A.

METHODS

In a cross-sectional observational study, ultrasound measurements of fetal long bones and fluorimetric immunoassays for maternal serum PAPP-A were performed in 514 singleton pregnancies at 10-14 weeks of gestation.

RESULTS

There were 501 uncomplicated pregnancies. There were significant correlations between PAPP-A values and length of humerus, femur and tibia [r values 0.12 (P = 0.01), 0.11 (P = 0.01) and 0.10 (P = 0.03), respectively]. The association with the length of ulna and foot did not reach statistical significance (r values 0.08 and -0.03, respectively).

CONCLUSIONS

Maternal serum PAPP-A levels at 10-14 weeks of gestation are significantly associated with the length of fetal long bones such as humerus, femur and tibia. This provides further evidence that PAPP-A may be involved in the regulation of bone development.

[Mirror pre-eclampsia: Ballantyne's syndrome. Two cases]

We report two cases of Ballantyne's syndrome which was first described in association with foeto-placental hydrops caused by rhesus isoimmunization. Our two cases occurred in association with materno-fetal parvovirus infection. Although the pathogenic mechanism remains to be fully elucidated, fluid retention and hyperplacentation are the main features. Together with these two case reports, a literature review confirmed the diverse nonimmunological etiologies associated with Ballantyne's syndrome. Clinicians should be aware of this particular presentation of hydrops fetalis resulting from a mechanism different from hypotrophic placentation because specific etiological treatment can avoid unnecessary pregnancy termination. Pre-conception counselling is also different.

Screening in women's health, with emphasis on fetal Down's syndrome, breast cancer and osteoporosis

Screening tests have become increasingly popular in women's health care over the last two decades. The initiative for screening is typically generated by either an agency or the health care professional being consulted for some reason. In many instances, however, the demand for screening tests is patient driven with the health care provider being poorly prepared to determine the usefulness of screening. This review illustrates the complexity of screening using three disorders where early detection and treatment have the potential to improve the quality and longevity of life. Prenatal diagnosis of Down's syndrome does not offer the parents the opportunity for cure but does offer the opportunity for education and rational choice as the impact of the diagnosis on the family is weighed. The evidence for breast cancer screening is more persuasive for older than younger women, but even in older women, there is a balance of risks and benefits. Treatment options for osteoporosis have improved in terms of reductions in fracture risk as well as beneficial effects on bone density, but evidence of the effectiveness of a screening programme for this condition in an unselected population is lacking. Ultimately, it is crucial that women be provided with clear and comprehensive information about the screening programme, in terms of possible gains but also costs of various kinds: physical, economic and psychological.

Prediction of pre-eclampsia by uterine artery Doppler ultrasonography and maternal serum pregnancy-associated plasma protein-A, free beta-human chorionic gonadotropin, activin A and inhibin A at 22 + 0 to 24 + 6 weeks' gestation

OBJECTIVE

To investigate the potential value of combining uterine artery Doppler ultrasonography with the measurement of maternal serum pregnancy-associated plasma protein-A (PAPP-A), free beta-human chorionic gonadotropin (beta-hCG), activin A and inhibin A at 22 + 0 to 24 + 6 weeks' gestation, in the prediction of pregnancies that subsequently develop pre-eclampsia.

METHODS

The maternal serum PAPP-A, free beta-hCG, activin A and inhibin A concentrations at 22 + 0 to 24 + 6 weeks' gestation were measured in samples obtained from women with singleton pregnancies who participated in a screening study for pre-eclampsia by transvaginal color flow Doppler measurement of the uterine artery pulsatility index (PI). A search was made of the database to identify those who subsequently developed pre-eclampsia (n = 24) and a group of controls with normal outcome (n = 144). Regression analysis was performed to establish any relationship between the biochemical markers themselves and between the biochemical markers and uterine artery mean PI. A multivariate Gaussian model combining various biochemical markers with uterine artery mean PI was developed using standard statistical modeling techniques and the performance of such models in discriminating cases with pre-eclampsia was evaluated by receiver-operating characteristics curve (ROC) analysis.

RESULTS

In the pre-eclampsia group, compared to the controls, the uterine artery mean PI and the maternal serum levels of PAPP-A, free beta-hCG, activin A and inhibin A were significantly increased. The predicted detection rates of pre-eclampsia, for a false positive rate of 5%, was 50% by uterine artery mean PI, 5% by PAPP-A, 10% by free beta-hCG, 35% by inhibin A and 44% by activin A. Screening by a combination of uterine artery mean PI and maternal serum activin A and inhibin A could detect 75% and 92% of patients who subsequently developed pre-eclampsia, for false positive rates of 5% and 10%, respectively.

CONCLUSION

Screening for pre-eclampsia by uterine artery PI at 22 + 0 to 24 + 6 weeks' gestation can be improved by measurement of activin A and inhibin A levels.

First-trimester combined screening for Down syndrome and other fetal anomalies

OBJECTIVE

This study assessed fetal outcomes for pregnancies identified at increased risk for Down syndrome by first-trimester combined ultrasound examination and maternal serum biochemistry screening.

METHODS

First-trimester combined screening data were obtained from ultrasound clinics across Western Australia between August 2001 and October 2003. Prenatal screening data were linked with pregnancy outcome information held in state health database registers using probabilistic record-linkage techniques.

RESULTS

In 50 of the 60 pregnancies affected by Down syndrome, the adjusted risk was greater than 1 in 300, providing a detection rate of 83% (95% confidence interval [CI] 74-93%). Among all women screened (n = 22,280), 827 had increased risk results but did not have a Down syndrome pregnancy, representing a false-positive rate of 3.7% (95% CI 3.5-3.9%). Ten cases of Down syndrome were detected among women considered not at increased risk, consistent with a false-negative rate of 1 in 2,227. First-trimester combined screening reduced the number of Down syndrome births by 50 in 22,280 (2.24 cases per 1,000 births), which represents the detection of one case of fetal Down syndrome for every 446 women screened. Furthermore, 25% of pregnancies with other birth defects occurred among those identified at increased risk of Down syndrome, and 1 in 8 pregnancies at increased risk were found to have a significant chromosomal or structural defect.

CONCLUSION

First-trimester combined screening in Western Australia detected 83% (95% CI 74-93%) of Down syndrome pregnancies at a 3.7% (95% CI 3.5-3.9%) false-positive rate.

LEVEL OF EVIDENCE

II-2.