First- and second-trimester maternal serum markers of pre-eclampsia in twin pregnancy

Low PAPPA and Its Association with Adverse Pregnancy Outcomes in Twin Pregnancies: A Systematic Review of the Literature and Meta-Analysis

Background: It is well established in the literature that pregnancy-associated plasma protein-A (PAPP-A) is linked to several adverse pregnancy outcomes, including pre-eclampsia (PE), fetal growth restriction (FGR), and preterm birth (PTB) in singleton pregnancies. However, data regarding such an association in twin pregnancies are lacking. The primary goal of this systematic review and meta-analysis was to assess the potential value of low PAPP-A levels in the prediction of the subsequent development of hypertensive disorders of pregnancy (HDPs), PTB, and small for gestational age (SGA)/FGR fetuses in twin pregnancies and investigate its association with the development of gestational diabetes, intrauterine death (IUD) of at least one twin, and birth weight discordance (BWD) among the fetuses. Methods: Medline, Scopus, CENTRAL, Clinicaltrials.gov, and Google Scholar databases were systematically searched from inception until 31 July 2024. All observational studies reporting low PAPP-A levels after the performance of the first-trimester combined test as part of the screening for chromosomal abnormalities with reported adverse pregnancy outcomes were included. Results: The current systematic review encompassed a total of 11 studies (among which 6 were included in the current meta-analysis) that enrolled a total of 3741 patients. Low PAPP-A levels were not associated with HDPs (OR 1.25, 95% CI 0.78, 2.02, I-square test: 13%). Low PAPP-A levels were positively associated with both the development of preterm birth prior to 32 (OR 2.85, 95% CI 1.70, 4.77, I-square test: 0%) and 34 weeks of gestational age (OR 2.09, 95% CI 1.34, 3.28, I-square test: 0%). Furthermore, low PAPP-A levels were positively associated with SGA/FGR (OR 1.58, 95% CI 1.04, 2.41, I-square test: 0%). Prediction intervals indicated that the sample size that was used did not suffice to support these findings in future studies. Conclusions: Our study indicated that low PAPP-A levels are correlated with an increased incidence of adverse perinatal outcomes in twin pregnancies. Identifying women at elevated risk for such adversities in twin pregnancies may facilitate appropriate management and potential interventions, but additional studies are required to identify the underlying mechanism linking PAPP-A with those obstetrical complications.

First-trimester serum biomarkers in twin pregnancies and adverse obstetric outcomes-a single center cohort study

PURPOSE

This study aimed to determine the association of first-trimester maternal serum biomarkers with preterm birth (PTB), fetal growth restriction (FGR) and hypertensive disorders of pregnancy (HDP) in twin pregnancies.

METHODS

This is a retrospective cohort study of twin pregnancies followed at Maternidade Dr. Alfredo da Costa, Lisbon, Portugal, between January 2010 and December 2022. We included women who completed first-trimester screening in our unit and had ongoing pregnancies with two live fetuses, and delivered after 24 weeks. Maternal characteristics, pregnancy-associated plasma protein-A (PAPP-A) and β-human chorionic gonadotropin (β-hCG) levels were analyzed for different outcomes: small for gestational age (SGA), gestational hypertension (GH), early and late-onset pre-eclampsia (PE), as well as the composite outcome of PTB associated with FGR and/or HDP. Univariable, multivariable logistic regression analyses and receiver-operating characteristic curve were used.

RESULTS

466 twin pregnancies met the inclusion criteria. Overall, 185 (39.7%) pregnancies were affected by SGA < 5th percentile and/or HDP. PAPP-A demonstrated a linear association with gestational age at birth and mean birth weight. PAPP-A proved to be an independent risk factor for SGA and PTB (< 34 and < 36 weeks) related to FGR and/or HDP. None of the women with PAPP-A MoM > 90th percentile developed early-onset PE or PTB < 34 weeks.

CONCLUSION

A high serum PAPP-A (> 90th percentile) ruled out early-onset PE and PTB < 34 weeks. Unless other major risk factors for hypertensive disorders are present, these women should not be considered candidates for aspirin prophylaxis. Nevertheless, close monitoring of all TwP for adverse obstetric outcomes is still recommended.

High sensitivity and specificity in fetal gender identification in the first trimester, using ultrasound and Noninvasive Prenatal Screening (NIPS) in twin pregnancies, a prospective study

INTRODUCTION

Determination of the fetal gender in the first trimester is important in twin pregnancy cases of familial X-linked genetic syndromes and helps determine chorionicity. We assessed and compared the accuracy of first-trimester ultrasound scans, and cell-free fetal DNA (CfDNA) in determining fetal gender in the first trimester of twin pregnancies.

METHODS

Women with twin pregnancies were recruited prospectively during the first trimester. Fetal gender was determined using both ultrasound scans and CfDNA screening. Both results were compared to the newborn gender after delivery.

RESULTS

A total of 113 women with twin pregnancies were enrolled. There was 100% sensitivity and specificity in Y chromosome detection using CfDNA. Gender assignment using ultrasound in any first-trimester scans was 79.7%. Accuracy level increased from 54.2% in CRL 45-54 mm to 87.7% in CRL 55-67 mm and 91.5% in CRL 67-87 mm. Male fetuses had significantly higher chances of a gender assignment error compared to female fetuses, odds ratio = 23.574 (CI 7.346 - 75.656).

CONCLUSIONS

CfDNA is highly sensitive and specific in determining the presence of the Y chromosome in twin pregnancies in the first trimester. Between CRL 55-87 mm, ultrasound scanning offers a highly accurate determination of fetal gender in twin pregnancies.

Screening for preeclampsia in twin pregnancies

Twin pregnancies are an important risk factor for preeclampsia, a hypertensive disorder of pregnancy that is associated with a significant risk of maternal and perinatal morbidity. Given the burden of preeclampsia, the identification of women at high risk in early pregnancy is essential to allow for preventive strategies and close monitoring. In singleton pregnancies, the risk factors for preeclampsia are well established, and a combined first-trimester prediction model has been shown to adequately predict preterm disease. Furthermore, intervention with low-dose aspirin at 150 mg/day in those identified as high-risk reduces the rate of preterm preeclampsia by 62%. In contrast, risk factors for preeclampsia in twin pregnancies are less established, the proposed screening models have shown poor performance with high false-positive rates, and the benefit of aspirin for the prevention of preeclampsia is not clearly demonstrated. In this review, we examine the literature assessing prediction and prevention of preeclampsia in twin pregnancies.

sFlt-1, Not PlGF, Is Related to Twin Gestation Choronicity in the First and Third Trimesters of Pregnancy

Background: Preeclampsia occurs more often in dichorionic than in monochorionic twin pregnancy. We hypothesize that serum concentrations of biomarkers: placental growth factor (PlGF), serum soluble fms-like tyrosine kinase-1 (sFlt-1), and endoglin (Eng) differ between monochorionic and dichorionic twin pregnancies. Methods: A prospective observational study including 43 monochorionic and 36 dichorionic twin gestation was conducted. Blood samples were collected twice from all participants: between 11 + 0 and 13 + 6 and between 32 + 0 and 34 + 0 weeks of gestation. PlGF, sFlt-1 and Eng were measured using immnunoenzymatic assays. Results: We found a significantly higher concentration of sFlt-1 in dichorionic in comparison to monochorionic pregnancies in both the first and third trimesters. PlGF and sEng levels did not differ between mono- and dichorionic gestation in both study periods. sFlt-1 level was related to twin gestation chorionicity, while PlGF expression was not. PlGF, sFlt-1 and sEng concentrations increased significantly during gestation and were much higher in the third trimester compared to the values measured in the first trimester. Conclusions: Angiogenic biomarkers expression differ between dichorionic and monochorionic twin pregnancy. The sFlt-1 level is related to chorionicity of a twin gestation.

False-Positive Maternal Serum Screens in the Second Trimester as Markers of Placentally Mediated Complications Later in Pregnancy: A Systematic Review and Meta-Analysis

BACKGROUND

Multiple-marker, maternal serum screening (MSS) has been the cornerstone of prenatal diagnosis since the 1980s. While combinations of these markers are used to predict fetal risk of Down syndrome and other genetic conditions, there is some evidence that individual markers may also predict nongenetic pregnancy complications, particularly those related to placental dysfunction. The objective of this meta-analysis was to investigate the utility of false-positive, second-trimester MSS for Down syndrome as a marker of placentally mediated complications amongst singleton pregnancies globally.

METHODS

Electronic searches of PubMed, Medline, Embase, CINAHL, Web of Science, Scopus, and grey literature to 2019 were performed to identify observational studies comparing risk of pregnancy complications amongst pregnancies with false-positive MSS versus controls. A random-effects model of pooled odds ratios by outcome of interest (stillbirth, preeclampsia, fetal growth restriction, and preterm birth) and subgrouped by type of MSS test (double-, triple-, and quadruple-marker MSS) was used.

RESULTS

16 studies enrolling 68515 pregnancies were included. There were increased odds of preeclampsia (OR 1.28, 95% CI 1.09-1.51) and stillbirth (OR 2.46, 95% CI 1.94-3.12) amongst pregnancies with false-positive MSS. There was no significant association with preterm birth or growth restriction.

CONCLUSIONS

There is some evidence of an association between false-positive, second-trimester MSS for Down syndrome and increased odds of preeclampsia and stillbirth. Future large-scale prospective studies are still needed to best determine the predictive value of false-positive MSS as a marker of placentally mediated complications later in pregnancy and evaluate potential clinical interventions to reduce these risks.

Pre-eclampsia screening in the first trimester - preemptive action to prevent the peril

Pre-eclampsia complicating 2-5% of pregnancies is an obstetrical syndrome associated with deleterious short-and long-term consequences to the gravid women, the fetus and the neonate. Majority of the obstetrical complications occur in early pre-eclampsia (requiring delivery <34 weeks). The risk factor based approach recommended by the professional organizations for pre-eclampsia screening has shown suboptimal clinical performance. The combined multimarker screening for pre-eclampsia encompassing documentation of maternal medical history, measurement of mean arterial pressure, estimation of the maternal serum levels of placental growth factor, pregnancy associated plasma protein-A, and recording the Uterine artery mean pulsatility index, performed in the first trimester between 11 and 13 + 6 weeks has proven to be an effective screening strategy. The a-priori risk is determined by multivariate analysis of the factors from history, while the other parameters are converted to log 10 transformed multiple of median values. Bayes' theorem is used to calculate the final risk. The above model has shown to detect 77% of preterm pre-eclampsia (<37 weeks), 96% of early preterm pre-eclampsia (<34 weeks), 38% of term pre-eclampsia and 54% of all pre-eclampsia, at a false positive rate of 10%. Uterine artery Doppler is key to pre-eclampsia screening. Currently a risk of >1:100 for pre-eclampsia developing before 37 weeks (preterm pre-eclampsia) is regarded as screen positive. Aspirin at a dose of 150 mg at bedtime given to screen positive subjects is associated with a significant reduction of preterm pre-eclampsia and early pre-eclampsia. The intervention is now supported by a well conducted randomized trial and metanalysis data. Aspirin acts by diminishing stores of constitutive cyclooxygenase enzyme in the non-nucleated platelets without disturbing systemic prostaglandin production. Selective use of aspirin in screen positive women is associated with a very low incidence of adverse maternal, fetal and neonatal side effects. The screening protocol can be applied to twin pregnancies albeit minor differences. Hence, screening for pre-eclampsia in first trimester, which is now endorsed by the federation of international obstetrical and gynecological societies, should be offered universally to all women at 11 to 13 + 6 weeks of gestation, followed by the administration of aspirin and serial maternal-fetal surveillance in the screen positive woman.

Maternal Serum Placental Growth Factor, Soluble Fms-Like Tyrosine Kinase-1, and Soluble Endoglin in Twin Gestations and the Risk of Preeclampsia-A Systematic Review

Multiple gestation is one of the key risk factors for the occurrence of preeclampsia (PE). Soluble fms-like tyrosine kinase-1, placental growth factor, and soluble endoglin are molecules involved in the process of angiogenesis with a proven role in the pathogenesis of PE. The aim of the review was to summarize available data on maternal serum levels of the above-mentioned factors and their usefulness in predicting PE in twin pregnancies. Only original research articles written in English were considered eligible. Reviews, chapters, case studies, conference papers, experts’ opinions, editorials, and letters were excluded from the analysis. No publication date limitations were imposed. The systematic literature search using PubMed/MEDLINE, Scopus, Embase, and Cochrane Library databases identified 338 articles, 10 of which were included in the final qualitative analyses. The included studies showed significant differences in maternal serum levels of the discussed factors between women with twin pregnancies with PE and those who did not develop PE, and their promising performance in predicting PE, alone or in combination with other factors. The identification of the most effective algorithms, their prompt introduction to the clinical practice, and further assessment of the real-life performance should become a priority.

The association between high-normal blood pressure and the development of preeclampsia in twin pregnancies

Objective: We sought to determine if women with twin pregnancies and blood pressure (BP) above the 95th percentile but within normal ranges (i.e. less than 140 systolic and 90 diastolic) are at increased risk of hypertensive disorders of pregnancy.Methods: Retrospective cohort study of all women with twin pregnancies being cared for by a single Maternal Fetal Medicine practice between 2012 and 2018. We identified all women who had a systolic blood pressure (SBP) or diastolic blood pressure (DBP) above the 95th percentile but less than 140 systolic and 90 diastolic at any point during pregnancy. Based on prior publications, the 95th percentile was defined as: a SBP 121-139 mmHg up to 30 weeks or 131-139 mmHg after 30 weeks, a DBP 81-89 mmHg up to 34 weeks or 85-89 mmHg after 34 weeks. We excluded women diagnosed with chronic hypertension either before or during pregnancy. The primary outcome was the development of preeclampsia. Chi-square and logistic regression were used.Results: A total of 457 patients met the inclusion criteria, of whom 109 (23.9%) had either a systolic or diastolic BP above the 95th percentile (but normal) at any time during pregnancy. These women were significantly more likely to develop preeclampsia (30.3 versus 12.6%, p < .001, aOR 2.32 (1.31, 4.09)) and gestational hypertension without preeclampsia (16.5 versus 4.6%, p < .001, aOR 4.27 (2.01, 9.07)).Conclusions: In women with twin pregnancies, a high-normal systolic or diastolic BP (above 120 systolic or 80 diastolic prior to 30 weeks, or above 130 systolic or 84 diastolic after 30 weeks) is associated with a significantly increased risk of gestational hypertension and preeclampsia.

Prediction and prevention of pre-eclampsia in Asian subpopulation

The benefit of the early administration of aspirin to reduce preterm pre-eclampsia among screened positive European women from multivariate algorithmic approach (ASPRE trial) has opened an intense debate on the feasibility of universal screening. This review aims to assess the new perspectives in the combined screening of pre-eclampsia in the first trimester of pregnancy and the chances for prevention using low-dose aspirin with special emphasis on the particularities of the Asian population. PubMed, CENTRAL and Embase databases were searched from inception until 15 November 2017 using combinations of the search terms: preeclampsia, Asian, prenatal screening, early prediction, ultrasonography, pregnancy, biomarker, mean arterial pressure, soluble fms-like tyrosine kinase-1, placental growth factor, pregnancy-associated plasma protein-A and pulsatility index. This is not a systematic review or meta-analysis, so the risk of bias of the selected published articles and heterogeneity among the studies need to be considered. The prevalence of pre-eclampsia and serum levels of biochemical markers in Asian are different from Caucasian women; hence, Asian ethnicity needs to be corrected for in the algorithmic assessment of multiple variables to improve the screening performance. Aspirin prophylaxis may still be viable in Asian women, but resource implication needs to be considered. Asian ethnicity should be taken into account before implementing pre-eclampsia screening strategies in the region. The variables included can be mixed and matched to achieve an optimal performance that is appropriate for economical restriction in individual countries.

Competing-risks model in screening for pre-eclampsia in twin pregnancy according to maternal factors and biomarkers at 11-13 weeks' gestation

OBJECTIVE

To develop a model for screening for pre-eclampsia (PE) in twin pregnancies based on maternal demographic characteristics and medical history and biomarkers at 11-13 weeks' gestation.

METHODS

This was a screening study in twin pregnancies at 11-13 weeks' gestation. Bayes theorem was used to combine the a-priori risk from maternal factors with various combinations of uterine artery pulsatility index (UtA-PI), mean arterial pressure (MAP), serum pregnancy-associated plasma protein-A (PAPP-A) and placental growth factor (PlGF) multiples of the median (MoM) values. The performance of screening for PE requiring delivery at < 32, < 37 and < 42 weeks' gestation was estimated in 1100 twin pregnancies and 35 948 singleton pregnancies with complete data on UtA-PI, MAP, PlGF and PAPP-A.

RESULTS

In twin pregnancies that developed PE, the values of MAP and UtA-PI were increased and the values of PlGF and PAPP-A were decreased. The distributions of log₁₀ MoM values of biomarkers with gestational age at delivery were similar to those that were previously reported in singleton pregnancies and it was therefore assumed that the same model could be used for both singleton and twin pregnancies. The performance of screening for PE by maternal factors was improved by the addition of MAP, UtA-PI and PlGF; there was no further improvement with the addition of PAPP-A. In a mixed population of singleton and twin pregnancies, combined screening by maternal factors, MAP, UtA-PI and PlGF and risk cut-off of 1 in 75 for PE at < 37 weeks, the detection rate of PE at < 32, < 37 and < 42 weeks in singleton pregnancies was 91%, 77% and 57%, respectively, at a screen-positive rate (SPR) of 13%; the respective rates for twin pregnancies were 100%, 99% and 97%, at a SPR of 75%.

CONCLUSION

First-trimester combined screening for PE in singleton pregnancies can be adapted for screening in twins, leading to detection of nearly all affected cases but at a high SPR. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Maternal serum placental growth factor and pregnancy-associated plasma protein A measured in the first trimester as parameters of subsequent pre-eclampsia and small-for-gestational-age infants: A prospective observational study

Objective

To examine the first-trimester maternal serum placental growth factor (PlGF) and pregnancy-associated plasma protein A (PAPP-A) levels in pregnancies associated with pre-eclampsia (PE) or small-for-gestational-age (SGA) infants, and determine the predictive accuracy of PlGF and of PAPP-A for either PE or SGA infants.

Methods

This prospective, observational study included 175 pregnant women, and of these women, due to participant withdrawal or loss to follow-up, delivery data were collected from the medical records of 155 women, including 4 who had twin pregnancies. The women's maternal history was recorded, and the PlGF and PAPP-A levels at 11 to 13 gestational weeks were measured. During the second trimester, the maternal uterine artery's systolic/diastolic ratio was measured. Multiples of the median (MoM) of PlGF and PAPP-A were determined, and the associations of these values with the risk factors of SGA and PE were evaluated. Logistic regression analysis was used to determine whether PlGF and PAPP-A are useful markers for predicting SGA infants.

Results

The PAPP-A MoM level was significantly lower in women with advanced maternal age, multipara women, and women with gestational diabetes than in their counterparts. The PlGF and PAPP-A MoM levels were higher in women with a twin pregnancy than in those with a singleton pregnancy. There was a significant relationship between the maternal serum PAPP-A MoM level in the first trimester and the uterine artery systolic/diastolic ratio in the second trimester. Results of logistic regression analysis showed that low PlGF and PAPP-A MoM levels were predictors of SGA infants (odds ratio, 0.143; 95% confidence interval, 0.025 to 0.806; odds ratio, 0.191; 95% confidence interval, 0.051 to 0.718, respectively).

Conclusion

PlGF and PAPP-A are potentially useful as first-trimester markers for SGA infants and some hypertensive disorders of pregnancy.