Prediction of early, intermediate and late pre-eclampsia from maternal factors, biophysical and biochemical markers at 11-13 weeks

A description of the methods of the Nulliparous Pregnancy Outcomes Study: monitoring mothers-to-be (nuMoM2b)

OBJECTIVE

The primary aim of the "Nulliparous Pregnancy Outcomes Study: monitoring mothers-to-be" is to determine maternal characteristics, which include genetic, physiologic response to pregnancy, and environmental factors that predict adverse pregnancy outcomes.

STUDY DESIGN

Nulliparous women in the first trimester of pregnancy were recruited into an observational cohort study. Participants were seen at 3 study visits during pregnancy and again at delivery. We collected data from in-clinic interviews, take-home surveys, clinical measurements, ultrasound studies, and chart abstractions. Maternal biospecimens (serum, plasma, urine, cervicovaginal fluid) at antepartum study visits and delivery specimens (placenta, umbilical cord, cord blood) were collected, processed, and stored. The primary outcome of the study was defined as pregnancy ending at <37+0 weeks' gestation. Key study hypotheses involve adverse pregnancy outcomes of spontaneous preterm birth, preeclampsia, and fetal growth restriction.

RESULTS

We recruited 10,037 women to the study. Basic characteristics of the cohort at screening are reported.

CONCLUSION

The "Nulliparous Pregnancy Outcomes Study: monitoring mothers-to-be" cohort study methods and procedures can help investigators when they plan future projects.

Dried blood spot measurement of pregnancy-associated plasma protein A (PAPP-A) and free β-subunit of human chorionic gonadotropin (β-hCG) from a low-resource setting

OBJECTIVES

The objectives of the article is to compare pregnancy-associated plasma protein A (PAPP-A) and free β-subunit of human chorionic gonadotropin (β-hCG) concentrations in dried blood spots (DBSs) with serum of samples obtained from a public hospital in a low-resource setting and to evaluate their stability.

METHODS

Serum and DBS samples were obtained by venipuncture and finger prick from 50 pregnant participants in a cohort study in a public hospital in Accra, Ghana. PAPP-A and β-hCG concentrations from serum and DBS were measured with an AutoDELFIA® (PerkinElmer, PerkinElmer, Turku, Finland) automatic immunoassay. Correlation and Passing-Bablok regression analyses were performed to compare marker levels.

RESULTS

High correlation (>0.9) was observed for PAPP-A and β-hCG levels between various sampling techniques. The β-hCG concentration was stable between DBS and serum, PAPP-A concentration consistently lower in DBS.

CONCLUSION

Our findings suggest that β-hCG can be reliably collected from DBS in low-resource tropical settings. The exact conditions of the clinical workflow necessary for reliable PAPP-A measurement in these settings need to be further developed in the future. These findings could have implications for prenatal screening programs feasibility in low-income and middle-income countries, as DBS provides an alternative minimally invasive sampling method, with advantages in sampling technique, stability, logistics, and potential application in low-resource settings.

Expression profile of C19MC microRNAs in placental tissue in pregnancy-related complications

To demonstrate that pregnancy-related complications are associated with alterations in placental microRNA expression. Gene expression of 15 C19MC microRNAs (miR-512-5p, miR-515-5p, miR-516-5p, miR-517-5p, miR-518b, miR-518f-5p, miR-519a, miR-519d, miR-519e-5p, miR-520a-5p, miR-520h, miR-524-5p, miR-525, miR-526a, and miR-526b) was assessed in placental tissues, compared between groups (21 gestational hypertension [GH], 63 preeclampsia, 36 fetal growth restriction [FGR], and 42 normal pregnancies), and correlated with the severity of the disease with respect to clinical signs, delivery date, and Doppler ultrasound parameters. The expression profile of microRNAs was different between pregnancy-related complications and controls. The downregulation of 4 of 15 (miR-517-5p, miR-519d, miR-520a-5p, and miR-525), 6 of 15 (miR-517-5p, miR-518f-5p, miR-519a, miR-519d, miR-520a-5p, and miR-525), and 11 of 15 (miR-515-5p, miR-517-5p, miR-518b, miR-518f-5p, miR-519a, miR-519d, miR-520a-5p, miR-520h, miR-524-5p, miR-525, and miR-526a) microRNAs was associated with GH, FGR, and preeclampsia, respectively. Sudden onset of severe preeclampsia requiring immediate termination of gestation and mild forms of preeclampsia (persisting for several weeks) were associated with similar microRNA expression profile (downregulation of miR-517-5p, miR-520a-5p, miR-524-5p, and miR-525). In addition, miR-519a was found to be associated with severe preeclampsia. The longer the pregnancy-related disorder lasted, the more extensive was the downregulation of microRNAs (miR-515-5p, miR-518b, miR-518f-5p, miR-519d, and miR-520h). The downregulation of some C19MC microRNAs is a common phenomenon shared between GH, preeclampsia, and FGR. On the other hand, some of the C19MC microRNAs are only downregulated just in preeclampsia.

Pregnancy outcome in proteinuria-onset and hypertension-onset preeclampsia

OBJECTIVE

To evaluate pregnancy outcome in preeclampsia (PE), according to the timing of onset of proteinuria and hypertension.

METHODS

Preeclamptic women were retrospectively divided into proteinuria-onset and hypertension-onset PE according to the first symptom. Maternal and perinatal outcome were assessed in both the groups.

RESULTS

One hundred and ninety five single pregnancies complicated by PE were included. According to the first symptom, they were divided into two groups: proteinuria-onset PE (n = 49, 25.1%) and hypertension-onset PE (n = 146, 74.9%). Pregnancy and neonatal outcome was significantly worse in proteinuria-onset PE.

CONCLUSION

Proteinuria-onset PE is associated with an increased risk of adverse pregnancy outcome than hypertension-onset PE.

Ultrasound Assessment of Umbilical Cord Morphology in the First Trimester: A Feasibility Study

Objective: The aim of this study was to determine whether morphology and measurement of the umbilical cord could be accurately assessed at the time of the 11- to 13+6-week scan. Methods: We conducted a prospective study of 100 consecutive women with singleton pregnancies at 11-13+6 weeks' gestation who were seen for routine aneuploidy screening. Transabdominal ultrasound scans were performed, and the distance between two adjacent coils of the umbilical artery was measured in a free loop of umbilical cord. The antenatal umbilical coiling index (aUCI) was calculated as the inverse of this measurement (aUCI = 1/intercoil distance in cm). The maximum diameter of the umbilical vein was measured. Umbilical venous blood flow velocity was obtained using standard Doppler technique. Interobserver variability was assessed. A subjective assessment of the cord was performed using the Sepulveda system of classification to compare the reproducibility of the observations between two observers. Results: The intended measurements could be obtained in all cases. The aUCI was found to decrease with advancing gestation, while the umbilical venous diameter increased with gestation. The umbilical venous blood flow velocity also increased with gestation. Interobserver consistency in the objective measurement of the aUCI was poor (kappa 0.146). However, the Sepulveda classification system was found to be applicable and reproducible at this period of gestation (kappa 0.601). Conclusions: Umbilical cord morphology can be consistently studied in the first trimester. A subjective method of evaluation of the morphology may be a more reproducible technique until measurement strategies are refined and operator experience developed.

Predictive value of angiogenic factors, clinical risk factors and uterine artery Doppler for pre-eclampsia and fetal growth restriction in second and third trimester pregnancies in an Ecuadorian population

OBJECTIVE

To evaluate the performance of angiogenic factors, maternal risks and uterine artery Doppler (UAD) in the prediction of pre-eclampsia (PE) and fetal growth restriction (FGR) in a high-risk Ecuadorian population.

METHODS

Patients with singleton pregnancies (n = 346) were investigated at two clinical visits (18-25 weeks and 28-32 weeks). Mean uterine artery (UA), pulsatility index (PI) and maternal biomarkers (soluble fms-like tyrosine kinase-1, placental growth factor, sFlt-1/PLGF ratio) were obtained. The main endpoints were PE and FGR. UA PI and angiogenic factor levels were compared for the groups with PE (n = 34), FGR (n = 26), PE & FGR (n = 14) and controls (n = 272). Multivariable stepwise logistic regression was used to construct prediction models.

RESULTS

Pregnancies with either FGR or PE & FGR exhibited in the second trimester a significantly higher mean UA PI and sFlt-1/PLGF ratio and lower PLGF values compared to controls. In the third trimester, all groups with adverse outcome demonstrated significantly lower PLGF levels and a higher sFlt-1/PLGF ratio compared to normal pregnancies. Differences were most pronounced for pregnancies that developed PE and FGR for both time intervals. The combination of UAD and sFlt-1/PLGF ratio improved the predictive capacity for PE and FGR compared to each parameter alone. The best performance was obtained by integrating anamnestic risk factors, resulting in an area under the receiver operating curve for PE of 0.85 and 0.89 and for FGR of 0.79 and 0.77 in the second and third trimester, respectively.

CONCLUSION

In a high-altitude Ecuadorian population, angiogenic factors and UA PI were useful tools in the prediction of PE and/or FGR. The highest performance was achieved by the combination of these factors, including obstetric and medical history.

Influence of Sampling Site on Uterine Artery Doppler Indices at 11-13+6 Weeks Gestation

Introduction: Uterine artery pulsatility index (PI) is a key variable in the first trimester screening for pre-eclampsia. The aims of the study were to examine the effect of sampling the uterine arteries at a site distal to the level of the internal os, and to determine a lower limit of peak systolic velocity (PSV) to establish an auditable standard. Material and Methods: PI and PSV measurements were performed at 11-13+6 weeks' gestation at two sites: at the level of the internal os and 3 cm distal to the internal os. Comparative analyses utilised the Student's paired t-test. A 90% reference interval of transformed PSV measurements at the internal os was generated by polynomial regression. Results: There was a significant reduction in both the PI (14.9%) and the PSV (17.4%) when measured at the distal site compared to the level of the internal os (both p < 0.001). The best estimated 5th centile for uterine artery PSV at 11-13+6 weeks was 60.9 cm/s. Conclusion: PI measurements performed distal to the internal os are significantly lower and will result in inaccurate pre-eclampsia risk assessment. PSV measurements below 60 cm/s are likely to indicate an incorrect sampling site. Development of auditable measurement standards is important to ensure accuracy of prospective pre-eclampsia screening.

Forms of Circulating Luteinizing Hormone Human Chorionic Gonadotropin Receptor for the Prediction of Early and Late Preeclampsia in the First Trimester of Pregnancy

OBJECTIVE

To explore the value of circulating luteinizing human chorionic gonadotropin receptor (LHCGR) forms for the prediction of preeclampsia (PE) in the first trimester of pregnancy.

METHODS

Case-control study, based on a cohort of 5,759 pregnancies, including 20 early PE, 20 late PE, and 300 controls. We recorded/measured maternal characteristics, mean arterial pressure (MAP), uterine artery (UtA) Doppler, placental growth factor (PlGF), soluble Fms-like tyrosine kinase-1 (sFtl-1), and LHCGR forms (hCG-LHCGR and soluble LHCGR), and their independent predictive values were analyzed by logistic regression.

RESULTS

For early PE, the model included black ethnicity, chronic hypertension, previous PE, MAP, UtA Doppler, PlGF, sFlt-1, and LHCGR forms, achieving detection rates (DR) of 83% at 10% of false-positive rates (FPR) [AUC: 0.961 (95% CI: 0.921-1)]. For late PE, the model included body mass index, previous PE, UtA Doppler, PlGF, sFlt-1, and LHCGR forms, with DR of 75% at 10% of FPR [AUC: 0.923 (95% CI: 0.871-0.976)]. In both early and late PE, LHCGR forms improved DR by 6-15%.

CONCLUSIONS

LHCGR forms improved the prediction for early and late PE. These results should be confirmed in larger prospective studies.

Update on the pathophysiological implications and clinical role of angiogenic factors in pregnancy

Angiogenic markers are now being incorporated into clinical practice for the screening, diagnosing, and monitoring of preeclampsia. Pregnancy requires both vasculogenesis and angiogenesis in the fetal compartment and angiogenesis in the maternal compartment. Abnormal angiogenesis in the placenta determines impaired remodeling of the maternal spiral arteries and placental underperfusion that may ultimately lead to fetal growth restriction and maternal preeclampsia. The dysregulation of angiogenesis in the placenta and maternal-fetal circulation has emerged as one of the main pathophysiological features in the development of placental insufficiency and its clinical consequences. Abnormal angiogenesis has also been related to other obstetric and fetal conditions such as peripartum cardiomyopathy and fetal cardiac defects. This opens up new challenges for our understanding of angiogenic involvement in maternal cardiovascular function and fetal cardiac development, and it offers new clinical opportunities. This review summarizes the current knowledge of the pathophysiological implications and the clinical role of angiogenic factors in pregnancy.

Longitudinal changes in maternal corin and mid-regional proatrial natriuretic peptide in women at risk of pre-eclampsia

OBJECTIVE

Corin, an atrial natriuretic peptide-converting enzyme, has been found to promote trophoblast invasion and spiral artery remodeling. Yet, elevated maternal plasma atrial natriuretic peptide (ANP) and corin levels have been reported in pregnancies complicated by pre-eclampsia (PE). The aim of this study was to investigate longitudinal changes in maternal plasma levels of corin and mid-regional proatrial natriuretic peptide (MR-PANP) in pregnancies that develop PE and gestational hypertension (GH).

METHODS

This was a nested case-control study drawn from a larger prospective longitudinal study in singleton pregnancies identified as being at high risk for PE by screening at 11 + 0 to 13 + 6 weeks' gestation. Blood samples were taken every 4 weeks until delivery. Values were compared in pregnancies that developed preterm PE (requiring delivery before 37 weeks' gestation), term PE, GH and those that remained normotensive.

RESULTS

A total of 471 samples were analyzed from 122 women, including 85 that remained normotensive, 12 that developed GH, 13 term PE and 12 preterm PE. In the normotensive group, log10 corin levels were associated with gestational age (P < 0.01), whereas log10 MR-PANP levels were not. In the preterm-PE group, compared with the normotensive group, corin was significantly lower until 20 weeks' gestation (P = 0.001). In the GH and term-PE groups, corin did not differ significantly from the normotensive group (P = 0.637 and P = 0.161, respectively). Compared with the normotensive group, MR-PANP levels were significantly higher in the pregnancies that developed preterm PE and GH (P = 0.046 and P = 0.019, respectively), but not term PE (P = 0.467).

CONCLUSION

Maternal-plasma corin and MR-PANP could potentially be useful biomarkers for the prediction of preterm PE.

Risk assessment for preeclampsia in nulliparous women at 11-13 weeks gestational age: prospective evaluation of two algorithms

OBJECTIVE

To evaluate two algorithms for prediction of preeclampsia in a population of nulliparous women in Norway.

DESIGN

Prospective screening study.

SETTING

National Centre for Fetal Medicine in Trondheim, Norway.

POPULATION

Five hundred and forty-one nulliparous women.

METHODS

The women were examined between 11(+0) and 13(+6) weeks with interviews for maternal characteristics and measurements of mean arterial pressure, uterine artery pulsatility index, pregnancy-associated plasma protein A and placental growth factor. The First Trimester Screening Program version 2.8 by The Fetal Medicine Foundation (FMF) was compared with the Preeclampsia Predictor TM version 1 revision 2 by Perkin Elmer (PREDICTOR).

MAIN OUTCOME MEASURES

Prediction of preeclampsia requiring delivery before 37 weeks, before 42 weeks and late preeclampsia (delivery after 34 weeks).

RESULTS

The performance of the two algorithms was similar, but quite poor, for prediction of preeclampsia requiring delivery before 42 weeks with an area under the curve of 0.77 (0.67-0.87) and sensitivity 40% (95% CI 19.1-63.9) at a fixed 10% false positive rate for FMF and 0.74 (0.63-0.84) and sensitivity 30% (95% CI 11.9-54.3) at a fixed 10% false positive rate for PREDICTOR. The FMF algorithm for preeclampsia requiring delivery <37 weeks had an area under the curve of 0.94 (0.86-1.0) and sensitivity of 80% (95% CI 28.4-99.5) at a 10% fixed false positive rate.

CONCLUSIONS

Fetal Medicine Foundation and PREDICTOR algorithms had similar and only modest performance in predicting preeclampsia. The results indicate that the FMF algorithm is suitable for prediction of preterm preeclampsia.

Nichtinvasive Pränataldiagnostik

Das Ersttrimesterscreening zur Risikobestimmung für die Trisomien 21, 18 und 13 hat sich in den letzten 15 Jahren in Deutschland etabliert. Die optimale Durchführung setzt die Einhaltung bestimmter Messkriterien beim Ultraschall und bei der biochemischen Analyse voraus sowie die Benutzung evaluierter Risikoberechnungsprogramme wie dem Berechnungsprogramm PRC der Fetal Medicine Foundation Deutschland (FMF-D). Durch die neue Version des Berechnungsprogramms PRC konnten die Trisomie-21-, -18- und -13-Detektionsraten erhöht werden bei gleichzeitiger Senkung der Falsch-positiv-Raten, was einen großen Fortschritt verglichen mit der mütterlichen Altersindikation darstellt.

Durch die Analyse der zellfreien fetalen DNA aus dem mütterlichen Plasma können seit 2 Jahren aber wesentlich bessere Screeningvorhersagen getroffen werden. Über 99 % aller Trisomie-21-Schwangerschaften können mit dieser Methodik als Risikogruppe beschrieben werden. Die Falsch-positiv-Rate liegt unter 1 %. Durch diese Methode ist ein Paradigmenwechsel in der Pränataldiagnostik zu erwarten.

First trimester screening for early and late preeclampsia based on maternal characteristics, biophysical parameters, and angiogenic factors

OBJECTIVE

The aim of this article is to develop the best first-trimester screening model for preeclampsia (PE) based on maternal characteristics, biophysical parameters, and angiogenic factors in a low-risk population.

METHODS

A prospective cohort of 9462 pregnancies undergoing first-trimester screening is used. Logistic regression predictive models were developed for early and late PE (cut-off of 34 weeks' gestation at delivery). Data included the a priori risk (maternal characteristics), mean arterial pressure (MAP), and uterine artery (UtA) Doppler (11-13 weeks) in all cases. Plasma levels (8-11 weeks) of human chorionic gonadotrophin, pregnancy-associated plasma protein A, placental growth factor (PlGF), and soluble Fms-like tyrosine kinase-1 (sFlt-1) were analyzed using a nested case-control study design.

RESULTS

The best model for early PE (n = 57, 0.6%) included a priori risk, MAP, UtA Doppler, PlGF, and sFlt-1 achieving detection rates of 87.7% and 91.2% for 5% and 10% false-positive rates, respectively (AUC: 0.98 [95% CI: 0.97-0.99]). For late PE (n = 246, 2.6%), the best model included the a priori risk, MAP, UtA Doppler, PlGF, and sFlt-1 achieving detection rates of 68.3% and 76.4% at 5% and 10% of false-positive rates, respectively (AUC: 0.87 [95% CI: 0.84-0.90]).

CONCLUSION

Preeclampsia can be predicted with high accuracy in general obstetric populations with a low risk for PE, by combined algorithms. Angiogenic factors substantially improved the prediction.

Longitudinal changes in maternal soluble endoglin and angiopoietin-2 in women at risk for pre-eclampsia

OBJECTIVE

To investigate longitudinal changes in maternal plasma levels of soluble endoglin (sEng) and angiopoietin-2 (Ang-2) in pregnant women who develop pre-eclampsia (PE) and gestational hypertension (GH).

METHODS

This was a nested case-control study drawn from a larger prospective longitudinal study in singleton pregnancies identified by screening at 11 + 0 to 13 + 6 weeks' gestation as being at high-risk for PE. Blood samples were taken every 4 weeks until delivery. Values were compared in women who developed preterm PE (requiring delivery before 37 weeks), term PE, GH and those who remained normotensive.

RESULTS

A total of 471 samples were analyzed in 122 women, comprising 85 who remained normotensive, 12 who developed GH, 13 who developed term PE and 12 who developed preterm PE. In the normotensive group, there was an increase in log10 sEng levels with gestational age. In the preterm PE group, compared with the normotensive group, sEng was higher from 18 weeks onwards, and the difference increased significantly with gestational age (P < 0.001). In the GH and term PE groups, sEng did not differ significantly from that of the normotensive group (P = 0.583 and P = 0.890, respectively). The square root of Ang-2 decreased significantly with gestational age, but did not differ significantly among the different outcome groups (P = 0.571).

CONCLUSION

Maternal plasma sEng, but not Ang-2, may be a useful mid- and late-gestation biomarker for the development of PE.

First-trimester maternal ophthalmic artery Doppler analysis for prediction of pre-eclampsia

OBJECTIVE

To determine the performance of a multiparametric test comprising maternal risk factors, uterine artery Doppler and ophthalmic artery Doppler in the first trimester of pregnancy for the prediction of pre-eclampsia (PE).

METHODS

This prospective observational cohort study recruited patients in the first trimester of pregnancy. Maternal uterine artery and ophthalmic artery Doppler assessments were performed in 440 singleton pregnancies at 11-14 weeks of gestation. Additional history was obtained through participant questionnaires, and follow-up occurred to discharge postdelivery. The normotensive and pre-eclamptic groups were compared using parametric (Student's t-test) and non-parametric (Mann-Whitney U-test) tests. Univariable and multivariable logistic regression analyses were performed to determine which biophysical factors, and which of the factors among the maternal characteristics and medical and obstetric history, had a significant contribution to the prediction of PE in a multiparametric model.

RESULTS

Thirty-one (7%) patients developed PE, including nine (2%) who required delivery before 34 weeks (early PE) and 22 (5%) with late PE. There were statistically significant differences in uterine artery pulsatility index (UtA-PI) and ophthalmic artery first diastolic peak (PD1) mean values between the PE and control groups. In a multiparametric model, both UtA-PI and PD1 achieved a 67% detection rate for early PE, although when combined, the detection rate only increased to 68%.

CONCLUSIONS

The efficiency of ophthalmic artery PD1 in the first trimester as a predictive marker for the later development of PE was approximately equal to that described for uterine artery Doppler. Although these findings do not support the replacement of uterine artery Doppler analysis in multiparametric predictive models for PE, they do provide novel insights into first-trimester maternal systemic vascular changes that precede the clinical development of this condition.

Psychological impact of first-trimester prevention for preeclampsia on anxiety

OBJECTIVE

This study aims to examine whether a first-trimester strategy of secondary prevention for preeclampsia increases anxiety in pregnant women.

METHODS

The anxiety levels of a cohort of women screened for preeclampsia at first trimester were measured by the Spielberg State-Trait Anxiety Inventory (STAI-S) and compared between women screened as low and high risk. In a subgroup of women, the anxiety levels were additionally measured at second and third trimester. A General Linear Model (GLM) for repeated measurements was performed to adjust for potential confounders (age, nulliparity and socio-economic level).

RESULTS

A total of 255 women (135 low-risk and 120 high-risk) were evaluated. No differences were found in the mean STAI-S scores between low-risk and high-risk women: 35 (SD 9.9) and 34.6 (SD 10.1); p = 0.77. The proportion of women with high anxiety was not significantly different between groups (28/134 [20.7%] vs 24/120 [20%]; p = 0.88). No differences were found in the subgroups (51 low-risk and 50 high-risk) in which the anxiety levels were also measured at second and third trimester: 35.8 (SD 8.8) vs 35.2 (SD 9.7), p = 0.74, and 37.2 (SD 9.4) vs 35.3 (SD 8.6), p = 0.3. These differences remained non-significant after adjustment for potential confounders.

CONCLUSION

A strategy of first-trimester screening for preeclampsia does not increase maternal anxiety.

First-trimester prediction of pre-eclampsia: external validity of algorithms in a prospectively enrolled cohort

OBJECTIVE

To evaluate the performance of published first-trimester prediction algorithms for pre-eclampsia (PE) in a prospectively enrolled cohort of women.

METHOD

A MEDLINE search identified first-trimester screening-prediction algorithms for early-onset (requiring delivery < 34 weeks) and late-onset (requiring delivery ≥ 34 weeks) PE. Maternal variables, ultrasound parameters and biomarkers were determined prospectively in singleton pregnancies enrolled between 9 and 14 weeks. Prediction algorithms were applied to this population to calculate predicted probabilities for PE. The performance of the prediction algorithms was compared with that in the original publication and evaluated for factors explaining differences in prediction.

RESULTS

Six early and two late PE prediction algorithms were applicable to 871-2962 women, depending on the variables required. The prevalence of early PE was 1.0-1.2% and of late PE was 4.1-5.0% in these patient subsets. One early PE prediction algorithm performed better than in the original publication (80% detection rate (DR) of early PE for 10% false-positive rate (FPR)); the remaining five prediction algorithms underperformed (29-53% DR). Prediction algorithms for late PE also underperformed (18-31% DR, 10% FPR). Applying the screening cut-offs based on the highest Youden index probability scores correctly detected 40-80% of women developing early PE and 71-82% who developed late PE. Exclusion of patients on first-trimester aspirin resulted in DRs of 40-83% and 65-82% for early and late PE, respectively.

CONCLUSION

First-trimester prediction algorithms for PE share a high negative predictive value if applied to an external population but underperform in their ability to correctly identify women who develop PE. Further research is required to determine the factors responsible for the suboptimal external validity.

Pre-eclampsia part 2: prediction, prevention and management

An antiangiogenic state might constitute a terminal pathway for the multiple aetiologies of pre-eclampsia, especially those resulting from placental abnormalities. The levels of angiogenic and antiangiogenic proteins in maternal blood change prior to a diagnosis of pre-eclampsia, correlate with disease severity and have prognostic value in identifying women who will develop maternal and/or perinatal complications. Potential interventions exist to ameliorate the imbalance of angiogenesis and, hence, might provide opportunities to improve maternal and/or perinatal outcomes in pre-eclampsia. Current strategies for managing pre-eclampsia consist of controlling hypertension, preventing seizures and timely delivery of the fetus. Prediction of pre-eclampsia in the first trimester is of great interest, as early administration of aspirin might reduce the risk of pre-eclampsia, albeit modestly. Combinations of biomarkers typically predict pre-eclampsia better than single biomarkers; however, the encouraging initial results of biomarker studies require external validation in other populations before they can be used to facilitate intervention in patients identified as at increased risk. Angiogenic and antiangiogenic factors might also be useful in triage of symptomatic patients with suspected pre-eclampsia, differentiating pre-eclampsia from exacerbations of pre-existing medical conditions and performing risk assessment in asymptomatic women. This Review article discusses the performance of predictive and prognostic biomarkers for pre-eclampsia, current strategies for preventing and managing the condition and its long-term consequences.

External validity of first-trimester algorithms in the prediction of pre-eclampsia disease severity

OBJECTIVE

To compare disease features in women with pre-eclampsia between those who are correctly identified (true positive) and those who are missed (false negative) when applying first-trimester prediction algorithms for pre-eclampsia to a prospectively enrolled population.

METHOD

Six first-trimester early (requiring delivery < 34 weeks' gestation) pre-eclampsia algorithms were applied to a prospective cohort of singleton pregnancies enrolled at first-trimester screening. Maternal outcomes, neonatal outcomes and severity parameters for pre-eclampsia were compared between true-positive and false-negative predictions.

RESULTS

Twenty of 2446 (0.8%) women developed early pre-eclampsia, with 65% of these developing severe features and 20% HELLP syndrome. At enrollment, true-positive cases were more likely to be African-American and chronically hypertensive, while false-negative cases were more likely to be Caucasian. At delivery, true-positive cases were more likely to have pre-eclampsia superimposed on hypertension, severely elevated blood pressure and creatinine level > 1.1 mg/dL. False-negative cases were more likely to have HELLP syndrome (all P < 0.05).

CONCLUSION

In an urban population with a high prevalence of chronic hypertension, patients who are correctly identified by first-trimester screening models are more likely to develop pre-eclampsia superimposed on chronic hypertension with severely elevated blood pressure and evidence of renal failure. In contrast, patients who are missed by these algorithms are more likely to have HELLP syndrome. Further research is needed to confirm these findings and the algorithm adjustments that may be necessary to better predict pre-eclampsia phenotypes.

First-trimester screening biochemical markers (free beta-subunit human chorionic gonadotropin, pregnancy-associated plasma protein-A) and risk of early fetal loss

AIM

The aim of this work was to assess the risk of early fetal loss (first trimester of pregnancy, 8-13 weeks of gestation) using the results of first-trimester screening (FTS) biochemical markers independently and combined.

METHODS

FTS results of 152 women who suffered early fetal loss were compared to a control group of 150 women with normal pregnancy outcomes. FTS biochemical markers were measured with a Delfia Xpress 6000 analyzer and biochemical risks for Down's and Edward's syndromes were calculated using Prenatal-Lifecycle version 3.0 software. Marker levels were standardized by calculating the gestational-specific multiple of the medians (MoM), further adjusted by maternal age, maternal weight, cigarette consumption and pre-existing type 1 diabetes mellitus. Receiver-operator curves were built to evaluate each marker and its combination.

RESULTS

Our results show that values of biochemical risk of t21 of more than 1 in 310 have a poor sensitivity to predict early fetal loss (31.4%) with a positive predictive value (PPV) for fetal loss of 67.7%. Values of pregnancy-associated plasma protein A (PAPP-A) MoM of less than 0.48 show a sensitivity of 62.1% and a PPV of 84.5% for early fetal loss; whereas for free β-human chorionic gonadotropin, values of MoM of less than 0.44 have a sensitivity of 66.4% with a PPV of 85.3%. A novel algorithm, consisting in the multiplication of both markers, shows for values of less than 0.48 a sensitivity of 83.1%, a specificity of 78.7% and a PPV of 77.1%.

CONCLUSION

Combined analysis of PAPP-A and free β-hCG appears to be a potential candidate to predict early fetal loss.

Placental Protein 13 (PP13) - A Placental Immunoregulatory Galectin Protecting Pregnancy

Galectins are glycan-binding proteins that regulate innate and adaptive immune responses, and some confer maternal-fetal immune tolerance in eutherian mammals. A chromosome 19 cluster of galectins has emerged in anthropoid primates, species with deep placentation and long gestation. Three of the five human cluster galectins are solely expressed in the placenta, where they may confer additional immunoregulatory functions to enable deep placentation. One of these is galectin-13, also known as Placental Protein 13 (PP13). It has a "jelly-roll" fold, carbohydrate-recognition domain and sugar-binding preference resembling other mammalian galectins. PP13 is predominantly expressed by the syncytiotrophoblast and released from the placenta into the maternal circulation. Its ability to induce apoptosis of activated T cells in vitro, and to divert and kill T cells as well as macrophages in the maternal decidua in situ, suggests important immune functions. Indeed, mutations in the promoter and an exon of LGALS13 presumably leading to altered or non-functional protein expression are associated with a higher frequency of preeclampsia and other obstetrical syndromes, which involve immune dysregulation. Moreover, decreased placental expression of PP13 and its low concentrations in first trimester maternal sera are associated with elevated risk of preeclampsia. Indeed, PP13 turned to be a good early biomarker to assess maternal risk for the subsequent development of pregnancy complications caused by impaired placentation. Due to the ischemic placental stress in preterm preeclampsia, there is increased trophoblastic shedding of PP13 immunopositive microvesicles starting in the second trimester, which leads to high maternal blood PP13 concentrations. Our meta-analysis suggests that this phenomenon may enable the potential use of PP13 in directing patient management near to or at the time of delivery. Recent findings on the beneficial effects of PP13 on decreasing blood pressure due to vasodilatation in pregnant animals suggest its therapeutic potential in preeclampsia.

Longitudinal changes in maternal hemodynamics in a population at risk for pre-eclampsia

OBJECTIVE

To investigate longitudinal changes in maternal hemodynamics from the first trimester onward in women who develop pre-eclampsia (PE) or gestational hypertension (GH).

METHODS

This was a prospective longitudinal study of singleton pregnancies identified by screening at 11 + 0 to 13 + 6 weeks' gestation as being at high risk for PE. Measurements of augmentation index (AIx), pulsed wave velocity (PWV) and aortic systolic blood pressure (SBPao) were taken every 4 weeks until delivery. Values were compared between women who developed preterm PE requiring delivery before 37 weeks, term PE or GH, and those who remained normotensive.

RESULTS

A total of 1198 observations were recorded in 245 women, including 181 who were normotensive, 22 with preterm PE, 22 with term PE and 20 with GH. In the normotensive group, there was a U-shaped relationship between AIx and gestational age with a trough at 25 weeks' gestation, whereas changes in levels of PWV or SBPao were minimal, with a mild increase from 25 and 30 weeks' gestation onward, respectively. In the GH and preterm PE groups, compared to the normotensive group, SBPao was higher and the difference did not change significantly with gestational age. In the term PE group, SBPao did not differ significantly from that in the normotensive group. In the preterm PE group compared to the normotensive group, PWV and AIx were significantly higher from 16-17 weeks' gestation onward and the difference increased with gestational age in both cases. In the term PE and GH groups, PWV and AIx did not differ significantly from normal.

CONCLUSION

This study describes temporal changes in AIx, PWV and SBPao in normotensive pregnant women and in women who develop PE or GH.

Early prediction of preeclampsia

Effective screening for the development of early onset preeclampsia (PE) can be provided in the first-trimester of pregnancy. Screening by a combination of maternal risk factors, uterine artery Doppler, mean arterial pressure, maternal serum pregnancy-associated plasma protein-A, and placental growth factor can identify about 95% of cases of early onset PE for a false-positive rate of 10%.

Maternal Serum Screening Markers and Adverse Outcome: A New Perspective

There have been a number of studies evaluating the association of aneuploidy serum markers with adverse pregnancy outcome. More recently, the development of potential treatments for these adverse outcomes as well as the introduction of cell-free fetal DNA (cffDNA) screening for aneuploidy necessitates a re-evaluation of the benefit of serum markers in the identification of adverse outcomes. Analysis of the literature indicates that the serum markers tend to perform better in identifying pregnancies at risk for the more severe but less frequent form of individual pregnancy complications rather than the more frequent but milder forms of the condition. As a result, studies which evaluate the association of biomarkers with a broad definition of a given condition may underestimate the ability of such markers to identify pregnancies that are destined to develop the more severe form of the condition. Consideration of general population screening using cffDNA solely must be weighed against the fact that traditional screening using serum markers enables detection of severe pregnancy complications, not detectable with cffDNA, of which many may be amenable to treatment options.

Down syndrome screening in assisted conception twins: an iatrogenic medical challenge

OBJECTIVE

The objective of this study was to provide a critical analysis of the impact of assisted conception on prenatal screening for Down syndrome (DS) in twin pregnancies and the value of various screening modalities for early detection of anomalies.

METHODS

The literature was searched using PubMed and the Cochrane Library focusing on prenatal screening and antenatal care of assisted-conception twin pregnancies.

RESULTS

Serum screening alone is of limited value in detecting aneuploid twins, because the unaffected cotwin can "mask" the abnormal serum results of an affected one. In addition, this test can designate the pregnancy as at high risk but not identify the affected fetus. Nuchal translucency (NT) screening is the best available modality and a highly effective screening method for twin pregnancies. Among twins, NT alone has a 69% DS detection rate, first-trimester combined NT and serum biochemistry has a 72% DS detection rate, and an integrated screen will have an 80% DS detection rate at a 5% FPR. The data in the literature concerning the effect of assisted conception on maternal serum screening markers in twin pregnancies are scarce.

CONCLUSIONS

Down syndrome screening in assisted-conception twins presents clinical and technical challenges. Therefore, assisted-conception twins need close monitoring from conception to delivery, by a practitioner familiar with the available screening modalities and their relative accuracy.

Competing risk model in screening for preeclampsia by mean arterial pressure and uterine artery pulsatility index at 30-33 weeks' gestation

OBJECTIVE

To assess risk for preeclampsia (PE) based on maternal characteristics, mean arterial pressure (MAP) and uterine artery pulsatility index (Ut-PI) at 30-33 weeks' gestation.

METHODS

Screening study in singleton pregnancies including 2,140 that subsequently developed PE and 83,615 that were unaffected by PE, gestational hypertension or delivery of small-for-gestational-age neonates (normal group). We developed a survival time model for the time of delivery for PE by combination of maternal characteristics and history with MAP and Ut-PI multiple of the median (MoM) values (biophysical test). Data on third-trimester MAP and Ut-PI were available in 350 cases of PE and 13,878 of the normal group. The detection rate of PE requiring delivery within 4, 6 and 8 weeks of the visit was estimated.

RESULTS

In pregnancies with PE the log10 MoM values of MAP and Ut-PI were inversely related to gestational age at delivery. Biophysical testing detected 90, 65 and 53% of PE with delivery within 4, 6 and 8 weeks of the visit, at a fixed false-positive rate of 5%.

INTERPRETATION

Testing by maternal characteristics, Ut-PI and MAP at 30-33 weeks could identify 90% of pregnancies developing PE and requiring delivery within the subsequent 4 weeks.

Mid-trimester maternal ADAM12 levels differ according to fetal gender in pregnancies complicated by preeclampsia

An overrepresentation of adverse pregnancy outcomes has been observed in pregnancies associated with a male fetus. We investigated the association between fetal gender and candidate biomarkers for preeclampsia. Proteins were quantified in samples taken at 20 weeks from women recruited to the SCreening fOr Pregnancy Endpoints (SCOPE) study (preeclampsia n = 150; no preeclampsia n = 450). In contrast to placental growth factor, soluble endoglin, and insulin-like growth factor acid labile subunit, levels of metallopeptidase domain 12 (ADAM12) at 20 weeks were dependent on fetal gender in pregnancies complicated by preeclampsia, for male (n = 73) fetuses the multiples of the median (MoM; interquartile range [IQR] 1.1-1.5) was 1.3, whereas for female fetuses (n = 75) MoM was 1.1 (1.0-1.3); P < .01. Prediction of preeclampsia using ADAM12 levels was improved for pregnancies associated with a male fetus (area under receiver-operator curve [AUC] 0.73 [95% confidence interval [CI] 0.67-0.80]) than that of a female fetus (AUC 0.62 [0.55-0.70]); P = .03. The data presented here fit a contemporary hypothesis that there is a difference between the genders in response to an adverse maternal environment and suggest that an alteration in ADAM12 may reflect an altered placental response in pregnancies subsequently complicated by preeclampsia.

Pregnancy-associated plasma protein A (PAPP-A) and preeclampsia

Pregnancy-associated plasma protein A (PAPP-A) is a key regulator of insulin-like growth factor bioavailability essential for normal fetal development. In maternal blood, this protein increases with gestational age and then rapidly decreases after delivery. It is routinely used for Down syndrome screening in the first trimester of pregnancy, and its decrease compared to a normal pregnancy indicates an increased risk for both chromosomal anomalies and adverse pregnancy outcomes. It belongs to a group of biomarkers that predict later preeclampsia development, primarily early onset preeclampsia; however, it should be combined with a Doppler ultrasonography of the uterine artery (pulsatile index) and other biochemical and maternal factors to achieve a higher detection rate with an acceptable false positivity rate. Some studies have demonstrated an even more pronounced decrease of PAPP-A in the early second trimester of pregnancy in women who subsequently develop preeclampsia compared with women who do not develop preeclampsia. Conversely, during the last trimester of pregnancy, its concentration increases even more in patients with preeclampsia than in patients without. It is also detectable at very low levels in nonpregnant individuals, and a higher concentration indicates an adverse effect in patients with acute coronary syndromes or stable atherosclerotic disease and in patients with end-stage renal disease who are being treated with hemodialysis.

Prenatal Screening Using Maternal Markers

Maternal markers are widely used to screen for fetal neural tube defects (NTDs), chromosomal abnormalities and cardiac defects. Some are beginning to broaden prenatal screening to include pregnancy complications such as pre-eclampsia. The methods initially developed for NTDs using a single marker have since been built upon to develop high performance multi-maker tests for chromosomal abnormalities. Although cell-free DNA testing is still too expensive to be considered for routine application in public health settings, it can be cost-effective when used in combination with existing multi-maker marker tests. The established screening methods can be readily applied in the first trimester to identify pregnancies at high risk of pre-eclampsia and offer prevention though aspirin treatment. Prenatal screening for fragile X syndrome might be adopted more widely if the test was to be framed as a form of maternal marker screening.

Usefulness of circulating microRNAs for the prediction of early preeclampsia at first-trimester of pregnancy

To assess the usefulness of circulating microRNAs (miRNAs) as non-invasive molecular biomarkers for early prediction of preeclampsia, a differential miRNA profiling analysis was performed in first-trimester pooled sera from 31 early preeclampsia patients, requiring delivery before 34 weeks of gestation, and 44 uncomplicated pregnancies using microfluidic arrays. Among a total of 754 miRNAs analyzed, the presence of 63 miRNAs (8%) was consistently documented in the sera from preeclampsia and control samples. Nevertheless, only 15 amplified miRNAs (2%) seemed to be differentially, although modestly, represented (fold change range: 0.4–1.4). After stem loop RT-qPCR from individual samples, the statistical analysis confirmed that none of the most consistent and differentially represented miRNAs (3 overrepresented and 4 underrepresented) were differentially abundant in serum from preeclamptic pregnancies compared with serum from normal pregnancies. Therefore, maternal serum miRNA assessment at first-trimester of pregnancy does not appear to have any predictive value for early preeclampsia.

Longitudinal changes in uterine artery Doppler and blood pressure and risk of pre-eclampsia

OBJECTIVE

To investigate longitudinal changes in the uterine artery mean pulsatility index (UtA-PI) and mean arterial pressure (MAP) in women who develop pre-eclampsia (PE) and gestational hypertension (GH).

METHODS

This was a prospective longitudinal study of singleton pregnancies identified by screening at 11 + 0 to 13 + 6 weeks' gestation as being at high risk for PE. Measurements of UtA-PI and MAP were taken every 4 weeks until delivery and were compared in women who developed preterm PE, requiring delivery before 37 weeks, term PE and GH with those in women who remained normotensive.

RESULTS

In the normal outcome group, UtA-PI decreased with gestational age and MAP decreased between 12 and 24 weeks and then increased. In the preterm PE group, as compared to the normal group, UtA-PI and MAP were higher from early pregnancy onward and the difference for both increased with gestational age. In the term PE group, UtA-PI was significantly increased only from 33 weeks onward and MAP was increased from 12 weeks onward but the difference from normal did not increase with gestation. In GH, UtA-PI did not differ significantly from normal but MAP was higher from 12 weeks onward.

CONCLUSION

The study describes temporal changes in UtA-PI and MAP in normal pregnancies and in women who develop PE and GH.

First-trimester uterine artery Doppler and adverse pregnancy outcome: a meta-analysis involving 55,974 women

OBJECTIVES

To determine the accuracy with which uterine artery Doppler in the first trimester of pregnancy predicts pre-eclampsia and fetal growth restriction, particularly early-onset disease.

METHODS

We searched MEDLINE (1951-2012), EMBASE (1980-2012) and the Cochrane Library (2012) for relevant citations without language restrictions. Two reviewers independently selected studies that evaluated the accuracy of first-trimester uterine artery Doppler to predict adverse pregnancy outcome and performed data extraction to construct 2 × 2 tables. We synthesized sensitivity and specificity for various Doppler indices using a bivariate random-effects model.

RESULTS

From 1866 citations, we identified 18 studies (55,974 women). The sensitivity and specificity of abnormal uterine artery flow velocity waveform (FVW) in the prediction of early-onset pre-eclampsia were 47.8% (95% CI: 39.0-56.8) and 92.1% (95% CI: 88.6-94.6), and in the prediction of early-onset fetal growth restriction were 39.2% (95% CI: 26.3-53.8) and 93.1% (95% CI: 90.6-95.0), respectively. The sensitivities for predicting any pre-eclampsia and fetal growth restriction were 26.4% (95% CI: 22.5-30.8) and 15.4% (95% CI: 12.4-18.9), respectively, and the specificities were 93.4% (95% CI: 90.4-95.5%) and 93.3% (95% CI: 90.9-95.1), respectively. The number needed to treat (NNT) with aspirin to prevent one case of early-onset pre-eclampsia fell from 1000 to 173 and from 2500 to 421 for background risks varying between 1% and 0.4%, respectively.

CONCLUSIONS

First-trimester uterine artery Doppler is a useful tool for predicting early-onset pre-eclampsia, as well as other adverse pregnancy outcomes. Based on the NNT, abnormal uterine artery Doppler in low-risk women achieves a sufficiently high performance to justify aspirin prophylaxis in those who test positive.

Predictive biomarkers of pre-eclampsia and effectiveness of preventative interventions for the disease

INTRODUCTION

Pre-eclampsia (PE) is one of the most common pregnancy complication characterized by placental and maternal vascular dysfunction. It affects about 3 - 8% of women during the second half of pregnancy and represents one of the major causes of neonatal morbidity and mortality. The etiology of PE largely remains unknown.

AREAS COVERED

PE is considered a syndrome with multisystem involvement, so the ideal predictive test for it should utilize a combination of many predictors. Measurement in early pregnancy of a variety of biophysical and biochemical markers implicated in the pathophysiology of PE associated with clinical risk factors has been proposed to predict the development of the syndrome, thereby mitigating an adverse outcome.

EXPERT OPINION

The identification of reliable indicators is a clinically relevant issue that could result in early therapeutic intervention and leading to the prevention of maternal and fetal injuries before the manifestation of clinical signs. Many factors complicate the prevention of PE cases. Most are attributed to unknown etiology, the low predictive value of current screening tests and the several presentations of the disease. Although preventative treatments have been studied extensively, an effective intervention to avoid the development of PE has not yet been discovered.

The vitamin E-binding protein afamin increases in maternal serum during pregnancy

Background

Afamin is a liver-derived plasma glycoprotein with vitamin E-binding properties and a putative function in fertility. This study evaluated serum afamin concentrations during and postpartum to uncomplicated pregnancies and investigated a potential association between afamin concentrations and pregnancy outcome.

Methods

Afamin serum concentrations were measured in women with uncomplicated pregnancies in a retrospective cohort (n = 466) at different gestational ages and a prospective observational study (n = 76) in the first, second and third trimester. Furthermore, afamin was determined in the first trimester in a cross-sectional pilot study including women with preeclampsia (PE), pregnancy-induced hypertension (PIH) and women without pregnancy complications (n = 13 each). Finally, expression of afamin was investigated in human placental tissue by RT-PCR and immunohistochemistry.

Results

Afamin concentrations increased linearly almost two-fold during pregnancy in both retrospective and prospective studies in women without pregnancy complications with median afamin serum concentrations of 61.9 mg/l, 79.6 mg/l, and 98.6 mg/l in the first, second, and third trimester, respectively. After delivery, median afamin concentrations decreased to baseline values of 54.6 mg/l. In the pilot study with pregnancy complications, women with PE displayed significantly higher median afamin concentrations than did women with uncomplicated pregnancy (70.0 mg/l vs. 55.4 mg/l, P = 0.007). Expression analyses revealed no placental afamin expression at either mRNA or protein level in uncomplicated pregnancy.

Conclusion

A linear increase in the maternally expressed glycoprotein afamin during pregnancy may serve as basic reference for subsequent investigations of afamin in pregnancy-related disorders.

•

Serum afamin concentrations during and postpartum to uncomplicated pregnancies were evaluated.

•

Analysis of afamin in cross-sectional pilot study in patients with pregnancy complications.

•

Afamin linearly increased two-fold in women with uncomplicated pregnancies.

•

First trimester serum values of afamin were significantly higher in women with pregnancy complications.

•

Lacking placental afamin expression suggests maternal origin of circulating afamin.

Added value of angiogenic factors for the prediction of early and late preeclampsia in the first trimester of pregnancy

OBJECTIVE

To explore the predictive role of angiogenic factors for the prediction of early and late preeclampsia (PE) in the first trimester.

METHODS

A nested case-control study, within a cohort of 5,759 pregnancies, including 28 cases of early, 84 of late PE (cut-off 34 weeks) and 84 controls. Maternal characteristics, mean blood pressure (MAP), uterine artery (UtA) Doppler (11-13 weeks), vascular endothelial growth factor, placental growth factor (PlGF), soluble Fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin (8-11 weeks) were measured/recorded. All parameters were normalized by logarithmic transformation; logistic regression analysis was used to predict PE.

RESULTS

For early PE, significant contributions were chronic hypertension, previous PE, MAP, UtA Doppler, PlGF and sFlt-1. A model including these predictors achieved detection rates (DR) of 77.8 and 88.9% for 5 and 10% false-positive rates (FPR), respectively (AUC 0.958; 95% CI 0.920-0.996). For late PE, significant contributions were provided by body mass index, previous PE, UtA Doppler, PlGF and sFlt-1. The model including these factors achieved DR of 51.2 and 69% at 5 and 10% FPR, respectively (AUC 0.888; 95% CI 0.840-0.936).

CONCLUSIONS

Among angiogenic factors, not only PlGF but also sFlt-1 substantially improve the prediction for early and late PE. The data need confirmation in larger studies.

Clinical applications of biomarkers in preeclampsia

Preeclampsia remains a significant cause of maternal morbidity and mortality worldwide. Prediction, diagnosis and management continue to be challenging but advances in the understanding of the pathophysiological processes underlying the disease has enabled identification of multiple biomarkers, some of which aid prediction of those at risk. Even in isolation, some of these biomarkers have demonstrated sufficient test performance for incorporation into clinical practice. A combination of the most promising biomarkers and clinical factors may improve risk prediction, and aid diagnosis and subsequent management through development of integrated clinical risk models. This article aims to review the literature relating to biomarkers in preeclampsia and summarize the possible clinical applications of these findings.

Antenatal telephone support intervention with and without uterine artery Doppler screening for low risk nulliparous women: a randomised controlled trial

BACKGROUND

The number of routine antenatal visits provided to low risk nulliparous women has been reduced in the UK, acknowledging this change in care may result in women being less satisfied with their care and having poorer psychosocial outcomes. The primary aim of the study was to investigate whether the provision of proactive telephone support intervention (TSI) with and without uterine artery Doppler screening (UADS) would reduce the total number of antenatal visits required. A secondary aim was to investigate whether the interventions affected psychological outcomes.

METHODS

A three-arm randomised controlled trial involving 840 low risk nulliparous women was conducted at a large maternity unit in North East England. All women received antenatal care in line with current UK guidance. Women in the TSI group (T) received calls from a midwife at 28, 33 and 36 weeks and women in the telephone and Doppler group (T + D) received the TSI and additional UADS at 20 weeks' gestation. The main outcome measure was the total number of scheduled and unscheduled antenatal visits received after 20 weeks' gestation.

RESULTS

The median number of unscheduled (n = 2.0), scheduled visits (n = 7.0) and mean number of total visits (n = 8.8) were similar in the three groups. The majority (67%) of additional antenatal visits were made to a Maternity Assessment Unit because of commonly occurring pregnancy complications. Additional TSI+/-UADS was not associated with differences in clinical outcomes, levels of anxiety, social support or satisfaction with care. There were challenges to the successful delivery of the telephone support intervention; 59% of women were contacted at 29 and 33 weeks gestation reducing to 52% of women at 37 weeks.

CONCLUSIONS

Provision of additional telephone support (with or without UADS) in low risk nulliparous women did not reduce the number of unscheduled antenatal visits or reduce anxiety. This study provides a useful insight into the reasons why this client group attend for unscheduled visits.

TRIAL REGISTRATION

ISRCTN62354584.

Including ethical considerations in models for first-trimester screening for pre-eclampsia

Recent efforts to develop reliable and efficient early pregnancy screening programmes for pre-eclampsia have focused on combining clinical, biochemical and biophysical markers. The same model has been used for first-trimester screening for fetal aneuploidies i.e. prenatal diagnosis (PD), which is routinely offered to all pregnant women in many developed countries. Some studies suggest combining PD and pre-eclampsia screening, so women can be offered testing for a number of conditions at the same clinical visit. A combination of these tests may be practical in terms of saving time and resources; however, the combination raises ethical issues. First-trimester PD and pre-eclampsia screening entail qualitative differences which alter the requirements for disclosure, non-directedness and consent with regard to the informed consent process. This article explores the differences related to the ethical issues raised by PD and pre-eclampsia in order to elucidate which factors are relevant to deciding the type of information and consent required in each context from the perspective of the ethical principles of beneficence and autonomy. Furthermore, it argues that ensuring respect for patient autonomy is context dependent and, consequently, pre-eclampsia screening and PD should be performed independently of one another.

First trimester pregnancy volumes and subsequent small for gestational age fetuses

OBJECTIVE

To examine whether in the first trimester, placental, gestational sac and fetal volumes are different in pregnancies that result in small for gestational age (SGA) compared to average for gestational age (AGA) neonates.

METHODS

Case-control study comparing first trimester 3D volumes of the placenta, the fetus and the gestational sac between SGA and AGA pregnancies. 3D volumes were acquired for quality assurance and documentation. Pregnancy volumes were calculated by the virtual organ computer-aided analysis technique. Linear regression analysis was used to compute a normal range for the placental, gestational sac and fetal volume based on the crown rump length (CRL) in AGA pregnancies. Multiple regression analysis was used to examine significant influencing covariates. A Student's t test was used to compare the difference between the SGA and AGA group.

RESULTS

The study population consisted of 19 first trimester pregnancies with subsequent SGA neonates and 105 control pregnancies. In the AGA group, all pregnancy volumes were significantly dependent on the CRL. After controlling the CRL effect, the placental, gestational sac and fetal volumes were not significantly different between the SGA and AGA group.

CONCLUSION

First trimester 3D pregnancy volume measurements are not different in SGA or AGA pregnancies.

First-trimester screening for early and late small-for-gestational-age neonates using maternal serum biochemistry, blood pressure and uterine artery Doppler

OBJECTIVE

To assess the effectiveness of first-trimester screening for early and late small-for-gestational-age (SGA) neonates using maternal serum biochemistry, blood pressure and uterine artery Doppler.

METHODS

This was a prospective study of 4970 women with a singleton pregnancy who underwent routine first-trimester screening between 2009 and 2011. A logistic regression-based predictive model for SGA, defined as birth weight < 10(th) percentile, divided into early- or late-onset based on gestational age at delivery before or after 34 weeks' gestation, was constructed. The model included maternal baseline characteristics: serum levels of pregnancy-associated plasma protein-A and free β-human chorionic gonadotropin at 8-12 weeks and blood pressure and uterine artery Doppler at 11 + 0 to 13 + 6 weeks.

RESULTS

The prevalence of early and late SGA was 0.6% and 7.9%, respectively. Association with pre-eclampsia was 67% and 8%, respectively. At a false-positive rate of 15%, the detection rate for early SGA was 73%; however it differed substantially for cases with and without pre-eclampsia (90% vs 40%). For late SGA, at false-positive rates of 15 and 50%, detection rates were 32% and 70%, respectively, and did not substantially differ between cases with and without pre-eclampsia.

CONCLUSIONS

First-trimester screening predicts early SGA mainly because of its strong association with pre-eclampsia. Although prediction of late SGA was poorer, at a high false-positive rate it might be considered as part of a first-trimester strategy to select women requiring ultrasound assessment in the third trimester.