Mean Arterial Pressure at 11 +0 to 13 +6 Weeks in the Prediction of Preeclampsia

First-Trimester Prediction Models Based on Maternal Characteristics for Adverse Pregnancy Outcomes: A Systematic Review and Meta-Analysis

BACKGROUND

Early risk stratification can facilitate timely interventions for adverse pregnancy outcomes, including preeclampsia (PE), small-for-gestational-age neonates (SGA), spontaneous preterm birth (sPTB) and gestational diabetes mellitus (GDM).

OBJECTIVES

To perform a systematic review and meta-analysis of first-trimester prediction models for adverse pregnancy outcomes.

SEARCH STRATEGY

The PubMed database was searched until 6 June 2024.

SELECTION CRITERIA

First-trimester prediction models based on maternal characteristics were included. Articles reporting on prediction models that comprised biochemical or ultrasound markers were excluded.

DATA COLLECTION AND ANALYSIS

Two authors identified articles, extracted data and assessed risk of bias and applicability using PROBAST.

MAIN RESULTS

A total of 77 articles were included, comprising 30 developed models for PE, 15 for SGA, 11 for sPTB and 35 for GDM. Discriminatory performance in terms of median area under the curve (AUC) of these models was 0.75 [IQR 0.69-0.78] for PE models, 0.62 [0.60-0.71] for SGA models of nulliparous women, 0.74 [0.72-0.74] for SGA models of multiparous women, 0.65 [0.61-0.67] for sPTB models of nulliparous women, 0.71 [0.68-0.74] for sPTB models of multiparous women and 0.71 [0.67-0.76] for GDM models. Internal validation was performed in 40/91 (43.9%) of the models. Model calibration was reported in 21/91 (23.1%) models. External validation was performed a total of 96 times in 45/91 (49.5%) of the models. High risk of bias was observed in 94.5% of the developed models and in 58.3% of the external validations.

CONCLUSIONS

Multiple first-trimester prediction models are available, but almost all suffer from high risk of bias, and internal and external validations were often not performed. Hence, methodological quality improvement and assessment of the clinical utility are needed.

Machine Learning Algorithms Versus Classical Regression Models in Pre-Eclampsia Prediction: A Systematic Review

PURPOSE OF REVIEW

Machine learning (ML) approaches are an emerging alternative for healthcare risk prediction. We aimed to synthesise the literature on ML and classical regression studies exploring potential prognostic factors and to compare prediction performance for pre-eclampsia.

RECENT FINDINGS

From 9382 studies retrieved, 82 were included. Sixty-six publications exclusively reported eighty-four classical regression models to predict variable timing of onset of pre-eclampsia. Another six publications reported purely ML algorithms, whilst another 10 publications reported ML algorithms and classical regression models in the same sample with 8 of 10 findings that ML algorithms outperformed classical regression models. The most frequent prognostic factors were age, pre-pregnancy body mass index, chronic medical conditions, parity, prior history of pre-eclampsia, mean arterial pressure, uterine artery pulsatility index, placental growth factor, and pregnancy-associated plasma protein A. Top performing ML algorithms were random forest (area under the curve (AUC) = 0.94, 95% confidence interval (CI) 0.91-0.96) and extreme gradient boosting (AUC = 0.92, 95% CI 0.90-0.94). The competing risk model had similar performance (AUC = 0.92, 95% CI 0.91-0.92) compared with a neural network. Calibration performance was not reported in the majority of publications. ML algorithms had better performance compared to classical regression models in pre-eclampsia prediction. Random forest and boosting-type algorithms had the best prediction performance. Further research should focus on comparing ML algorithms to classical regression models using the same samples and evaluation metrics to gain insight into their performance. External validation of ML algorithms is warranted to gain insights into their generalisability.

Externally validated prediction models for pre-eclampsia: systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis aimed to evaluate the performance of existing externally validated prediction models for pre-eclampsia (PE) (specifically, any-onset, early-onset, late-onset and preterm PE).

METHODS

A systematic search was conducted in five databases (MEDLINE, EMBASE, Emcare, CINAHL and Maternity & Infant Care Database) and using Google Scholar/reference search to identify studies based on the Population, Index prediction model, Comparator, Outcome, Timing and Setting (PICOTS) approach until 20 May 2023. We extracted data using the CHARMS checklist and appraised the risk of bias using the PROBAST tool. A meta-analysis of discrimination and calibration performance was conducted when appropriate.

RESULTS

Twenty-three studies reported 52 externally validated prediction models for PE (one preterm, 20 any-onset, 17 early-onset and 14 late-onset PE models). No model had the same set of predictors. Fifteen any-onset PE models were validated externally once, two were validated twice and three were validated three times, while the Fetal Medicine Foundation (FMF) competing-risks model for preterm PE prediction was validated widely in 16 different settings. The most common predictors were maternal characteristics (prepregnancy body mass index, prior PE, family history of PE, chronic medical conditions and ethnicity) and biomarkers (uterine artery pulsatility index and pregnancy-associated plasma protein-A). The FMF model for preterm PE (triple test plus maternal factors) had the best performance, with a pooled area under the receiver-operating-characteristics curve (AUC) of 0.90 (95% prediction interval (PI), 0.76-0.96), and was well calibrated. The other models generally had poor-to-good discrimination performance (median AUC, 0.66 (range, 0.53-0.77)) and were overfitted on external validation. Apart from the FMF model, only two models that were validated multiple times for any-onset PE prediction, which were based on maternal characteristics only, produced reasonable pooled AUCs of 0.71 (95% PI, 0.66-0.76) and 0.73 (95% PI, 0.55-0.86).

CONCLUSIONS

Existing externally validated prediction models for any-, early- and late-onset PE have limited discrimination and calibration performance, and include inconsistent input variables. The triple-test FMF model had outstanding discrimination performance in predicting preterm PE in numerous settings, but the inclusion of specialized biomarkers may limit feasibility and implementation outside of high-resource settings. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Preeclampsia prediction model using demographic, clinical, and sonographic data in the second trimester of Japanese nulliparous women

AIM

This study aimed to clarify the factors influencing preeclampsia (PE) development in nulliparous Japanese women and to develop a PE prediction model using second trimester sonographic and clinical data readily available to obstetricians.

METHODS

This historical cohort study examined the obstetric records of nulliparous women who delivered at Yamanashi Prefectural Central Hospital from January 2019 to May 2023. A model was constructed to predict the PE development rate, with a focus on 796 nulliparous women. The assessed outcome was PE, excluding superimposed PE. Data on maternal age, assisted reproductive technology, mean arterial pressure, uterine artery notching, and umbilical artery resistance index were extracted. Multivariable logistic regression analysis was conducted on these five factors.

RESULTS

The incidence of PE was 4.3% (34/796). Multivariable analysis indicated significant odds ratios for the association of PE with mean arterial pressure (adjusted odds ratio: 1.06, 95% confidence interval: 1.03-1.10) and uterine artery notching (adjusted odds ratio: 6.28, 95% confidence interval: 2.82-14.0) in nulliparous women. The PE prediction formula was established as follows: Probability of PE development (%) = (odds/1 + odds) × 100, odds = ex and x = -11.3 + 0.039 × maternal age (years) + 0.91 × assisted reproductive technology + 0.061 × mean arterial pressure (mmHg) + 1.84 × uterine artery notching + 1.84 × umbilical artery resistance index. The sensitivity and specificity of this model were 58.8% and 84.5%, respectively (area under the curve: 0.79).

CONCLUSIONS

This study is the first to provide a prediction formula targeting the Japanese population. Our specialized model for nulliparous women could guide obstetricians to educate women regarding the precise prospect of PE development.

Prediction of preeclampsia in asymptomatic women

Preeclampsia is a major cause of maternal and perinatal morbidity and mortality. It is important to identify women who are at high risk of developing this disorder in their first trimester of pregnancy to allow timely therapeutic intervention. The use of low-dose aspirin initiated before 16 weeks of gestation can significantly reduce the rate of preterm preeclampsia by 62 %. Effective screening recommended by the Fetal Medicine Foundation (FMF) consists of a combination of maternal risk factors, mean arterial pressure, uterine artery pulsatility index (UtA-PI) and placental growth factor (PLGF). The current model has detection rates of 90 %, 75 %, and 41 % for early, preterm, and term preeclampsia, respectively at 10 % false-positive rate. Similar risk assessment can be performed during the second trimester in all pregnant women irrespective of first trimester screening results. The use of PLGF, UtA-PI, sFlt-1 combined with other investigative tools are part of risk assessment.

Early Prediction of Hypertensive Diseases of Pregnancy by Using Combined Screening Methods in a Rural Population

INTRODUCTION

The most frequent medical issue during pregnancy is hypertension, which can complicate up to 10% to 15% of pregnancies worldwide. An estimated 14% of all maternal fatalities worldwide are thought to be caused by hypertensive disease of pregnancy, one of the main causes of maternal and fetal morbidity and mortality. Despite the fact that maternal mortality is substantially lower in high-income countries than in low- and middle-income countries, hypertension is still one of the leading causes of maternal death globally. Maternal mortality associated with hypertension fluctuated between 0.08 and 0.42 per 100,000 births between 2009 and 2015. In India, the estimated overall pooled prevalence of HDP was determined to be one out of 11 women, or 11% (95% CI, 5%-17%). Despite various government programs, there is still a high prevalence of hypertension, which calls for stakeholders and healthcare professionals to focus on providing both therapeutic and preventive care. The best solution is to concentrate more on the early detection of pregnancy-related hypertension and to guarantee its universal application so that proper care can be carried out to prevent maternal and fetal morbidity.

AIM

To estimate the predictive value of the combination of maternal characteristics, i.e., mean arterial pressure (MAP), biophysical evaluation (uterine artery Doppler), and biochemical markers (pregnancy-associated plasma protein A (PAPP-A)), in the first trimester of pregnancy for hypertensive diseases of pregnancy.

METHODOLOGY

It was a prospective observational study of longitudinal variety that took over 18 months in a tertiary care rural hospital. The number of women admitted to the hospital for labor care during 2019 was 5261. A total of 513 were diagnosed with hypertensive illnesses during pregnancy. At a prevalence rate of 10%, we calculated a sample size of 350 to achieve a sensitivity of 85% with an absolute error of 12.5% at a 95% CI. Maternal histories, such as age, education, socio-economic status, gravidity, and BMI, were taken along with three parameters, i.e., MAP, which was significant above 90 mmHg, uterine artery Doppler, which was taken significant above 1.69, and serum PAPP-A, which was significant at less than 0.69 ml/IU.

OBSERVATION AND RESULTS

We have found that the following are associated with the prediction of hypertension: among the maternal characteristics are advanced age >35 years, presence of body edema, and urine proteins along with MAP, uterine artery pulsatility index (UtA-PI), and PAPP-A are significant. The predictive accuracy of the combination of MAP, UtA-PI, and PAPP-A is also significant. We also found that there is a significant increase in cesarean sections and NICU admissions in hypertensive patients.

CONCLUSION

A combination of screening parameters, including MAP, UtA-PI, and PAPP-A, to predict early hypertensive disease of pregnancy is developed and tested.

The association between sleep-disordered breathing and maternal endothelial and metabolic markers in pregnancies complicated by obesity

STUDY OBJECTIVES

To evaluate the impact of sleep-disordered breathing (SDB) on vascular, angiogenic and metabolic analytes in pregnancy.

METHODS

Participants with a body mass index ≥30 kg/m2 underwent polysomnography at 14-20 weeks gestation (visit 1). Participants with SDB (defined as an apnea-hypopnea index ≥5 events/h) were then enrolled in a separate trial. SDB-negative participants returned for a polysomnogram at 28-31 weeks (visit 2) and were recategorized as persistent-negative SDB or new-onset SDB. Mean arterial blood pressure, mean uterine artery Doppler pulsatility index, endoglin, soluble Feline McDonough Sarcoma-like tyrosine kinase 1, placental growth factor, and the homeostatic model assessment for insulin resistance were measured after each visit. Our primary outcome was a composite of uterine artery Doppler pulsatility index, soluble FMS-like tyrosine kinase 1/placental growth factor ratio, and homeostatic model assessment for insulin resistance. For secondary analyses, each outcome variable was analyzed independently.

RESULTS

A total of 242 and 130 participants completed visit 1 and visit 2, respectively. Newly diagnosed SDB was present in 37% of individuals at visit 1 and 31% of individuals at visit 2. No significant differences in our composite outcome vector were observed in individuals with and without SDB at either visit. In our secondary analysis, mean arterial blood pressure (88.7 ± 7.3 mm Hg vs 85.4 ± 7.1 mm Hg, P = .04) and fasting glucose (92.4 ± 15.2 mg/dL vs 86.6 ± 11.5 mg/dL, P = .05) were higher in participants with early pregnancy SDB. These associations were not observed for new-onset SDB. No associations were observed between uterine artery Doppler pulsatility index and angiogenic markers and SDB in pregnancy.

CONCLUSIONS

SDB in early pregnancy was not associated with our composite primary outcome but was associated with higher mean arterial blood pressure and fasting glucose. The pathophysiologic changes that occur in pregnant individuals with SDB and how they lead to an increased risk of preeclampsia and gestational diabetes remain poorly understood.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Sleep Disordered Breathing, Obesity and Pregnancy Study (SOAP); URL: https://clinicaltrials.gov/ct2/show/NCT02086448; Identifier: NCT02086448.

CITATION

Onslow ML, Wolsk J, Wisniewski S, et al. The association between sleep-disordered breathing and maternal endothelial and metabolic markers in pregnancies complicated by obesity. J Clin Sleep Med. 2023;19(1):97-109.

Placental Growth Factor in First Trimester of Pregnancy for Prediction of Maternal and Perinatal Adverse Outcomes

Purpose of the study

Placental growth factor (PLGF) is an angiogenic factor in pregnancy. To find out correlation of plasma levels of placental growth factor in first trimester of pregnancy in Indian women who develop maternal and perinatal adverse outcomes was the aim of the study.

Methods

A prospective longitudinal noninterventional study was done in the department of Obstetrics and Gynecology after obtaining ethics approval. After enrolling patients in the first trimester (11 weeks to 13 weeks 6 days), a questionnaire was filled for demographic characteristics. Uterine artery doppler was done for every patient and blood sample (5 ml) was taken by venu puncture of median cubital vein. Serum levels of PLGF were measured by enzyme linked immunosorbent assay using Thermo Scientific Pierce Human PLGF kit (Thermo Fisher Scientific, Inc., Waltham, MA, USA). Patients were followed for their whole antenatal period and delivery outcomes.

Results

Incidence of preeclampsia in our study was 9.3% (15/161) and fetal growth restriction (FGR) was 19.8% (32/161). Neither BMI nor nulliparity was found to have statistically significant correlation with development of preeclampsia. However, history of preeclampsia was found to be significant risk factor for prediction of preeclampsia (p value < 0.04). Plasma levels of PLGF were significantly lower in preeclampsia and FGR group and this difference was statistically significant (p value < 0.04). 7.5% still born occurred in complicated group and 10% needed NNU/NICU admission in this group.

Conclusion

Measuring PLGF levels in first trimester of pregnancy can help in prediction of preeclampsia and FGR.

Diagnostic biomolecules and combination therapy for pre-eclampsia

Pre-eclampsia (PE), associated with placental malperfusion, is the primary reason for maternal and perinatal mortality and morbidity that can cause vascular endothelial injury and multi-organ injury. Despite considerable research efforts, no pharmaceutical has been shown to stop disease progression. If women precisely diagnosed with PE can achieve treatment at early gestation, the maternal and fetal outcomes can be maximally optimized by expectant management. Current diagnostic approaches applying maternal characteristics or biophysical markers, including blood test, urine analysis and biophysical profile, possess limitations in the precise diagnosis of PE. Biochemical factor research associated with PE development has generated ambitious diagnostic targets based on PE pathogenesis and dissecting molecular phenotypes. This review focuses on current developments in biochemical prediction of PE and the corresponding interventions to ameliorate disease progression, aiming to provide references for clinical diagnoses and treatments.

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.

First trimester preeclampsia screening and prediction

Preeclampsia is a major cause of maternal and perinatal morbidity and mortality. Early-onset disease requiring preterm delivery is associated with a higher risk of complications in both mothers and babies. Evidence suggests that the administration of low-dose aspirin initiated before 16 weeks' gestation significantly reduces the rate of preterm preeclampsia. Therefore, it is important to identify pregnant women at risk of developing preeclampsia during the first trimester of pregnancy, thus allowing timely therapeutic intervention. Several professional organizations such as the American College of Obstetricians and Gynecologists (ACOG) and National Institute for Health and Care Excellence (NICE) have proposed screening for preeclampsia based on maternal risk factors. The approach recommended by ACOG and NICE essentially treats each risk factor as a separate screening test with additive detection rate and screen-positive rate. Evidence has shown that preeclampsia screening based on the NICE and ACOG approach has suboptimal performance, as the NICE recommendation only achieves detection rates of 41% and 34%, with a 10% false-positive rate, for preterm and term preeclampsia, respectively. Screening based on the 2013 ACOG recommendation can only achieve detection rates of 5% and 2% for preterm and term preeclampsia, respectively, with a 0.2% false-positive rate. Various first trimester prediction models have been developed. Most of them have not undergone or failed external validation. However, it is worthy of note that the Fetal Medicine Foundation (FMF) first trimester prediction model (namely the triple test), which consists of a combination of maternal factors and measurements of mean arterial pressure, uterine artery pulsatility index, and serum placental growth factor, has undergone successful internal and external validation. The FMF triple test has detection rates of 90% and 75% for the prediction of early and preterm preeclampsia, respectively, with a 10% false-positive rate. Such performance of screening is superior to that of the traditional method by maternal risk factors alone. The use of the FMF prediction model, followed by the administration of low-dose aspirin, has been shown to reduce the rate of preterm preeclampsia by 62%. The number needed to screen to prevent 1 case of preterm preeclampsia by the FMF triple test is 250. The key to maintaining optimal screening performance is to establish standardized protocols for biomarker measurements and regular biomarker quality assessment, as inaccurate measurement can affect screening performance. Tools frequently used to assess quality control include the cumulative sum and target plot. Cumulative sum is a sensitive method to detect small shifts over time, and point of shift can be easily identified. Target plot is a tool to evaluate deviation from the expected multiple of median and the expected median of standard deviation. Target plot is easy to interpret and visualize. However, it is insensitive to detecting small deviations. Adherence to well-defined protocols for the measurements of mean arterial pressure, uterine artery pulsatility index, and placental growth factor is required. This article summarizes the existing literature on the different methods, recommendations by professional organizations, quality assessment of different components of risk assessment, and clinical implementation of the first trimester screening for preeclampsia.

Reducing the Risk of Preterm Preeclampsia: Comparison of Two First Trimester Screening and Treatment Strategies in a Single Centre in Switzerland

Introduction First trimester screening for preeclampsia (PE) is based on the combined risks model. Recent trials demonstrate that variations in multiple of the medians (MoMs) of the screening markers influence the performance of the algorithm in different populations. The aim of this study is to compare the performance of the algorithm in two cohorts with different prevention strategies.

Material and Methods All first trimester screening tests performed between January 2014 and April 2020 were included. Up to June 2017 pregnancies with a risk > 1 : 200 for early-onset PE (eoPE) were considered at risk and received 100 mg of aspirin (strategy A). From July 2017 onwards, pregnancies with a risk > 1 : 100 for preterm PE (pPE) received 150 mg of aspirin (strategy B). We compared the screen positive rates (SPR) and incidence of PE between the two screening approaches. Statistical analysis were performed with Graphpad 8.0.

Results 3552 pregnancies were included; 1577 pregnancies were screened according to strategy A, 1975 pregnancies according to strategy B. The screen positive rate (SPR) for strategy A and B was 8.9 and 16.9% respectively (p < 0.0001) while the incidence of PE was 1.41 and 1.84% respectively (p = ns).

Conclusion With a SPR of less than 10% we achieved a remarkably low rate of PE in our population, no further reduction in PE could be achieved by an increase in the SPR and LDA-prescription during the second screening period. The cut-off to define a pregnancy at risk for PE should be tailored to keep the SPR below 10% to avoid unnecessary treatment with aspirin.

Vibrational Spectroscopy: A Valuable Screening and Diagnostic Tool for Obstetric Disorders?

Preeclampsia (PE) is a common obstetric disorder typically affecting 2–8% of all pregnancies and can lead to several adverse obstetric outcomes for both mother and fetus with the greatest burden of severe outcomes in low middle-income countries (LMICs), therefore, screening for PE is vital. Globally, screening is based on maternal characteristics and medical history which are nonspecific for the disorder. In 2004, the World Health Organization acknowledged that no clinically useful test was able to predict the onset of PE, which prompted a universal search for alternative means of screening. Over the past decade or so, emphasis has been placed on the use of maternal characteristics in conjunction with biomarkers of disease combined into predictive algorithms, however these are yet to transition into the clinic and are cost prohibitive in LMICs. As a result, the screening paradigm for PE remains unchanged. It is evident that novel approaches are needed. Vibrational spectroscopy, specifically Raman spectroscopy and Fourier-transform infrared spectroscopy (FTIR), could provide better alternatives suited for implementation in low resource settings as no specialized reagents are required for conventional approaches and there is a drive to portable platforms usable in both urban and rual community settings. These techniques are based on light scattering and absorption, respectively, allowing detailed molecular analysis of samples to produce a unique molecular fingerprint of diseased states. The specificity of vibrational spectroscopy might well make it suited for application in other obstetric disorders such as gestational diabetes mellitus and obstetric cholestasis. In this review, we summarize current approaches sought as alternatives to current screening methodologies and introduce how vibrational spectroscopy could offer superior screening and diagnostic paradigms in obstetric care. Additionally, we propose a real benefit of such tools in LMICs where limited resources battle the higher prevalence of obstetric disorders.

Prospective Evaluation of International Prediction of Pregnancy Complications Collaborative Network Models for Prediction of Preeclampsia: Role of Serum sFlt-1 at 11-13 Weeks' Gestation

The study aimed to investigate whether serum sFlt-1 (soluble fms-like tyrosine kinase-1) at 11-13 weeks' gestation in pregnancies that subsequently developed preeclampsia was different from those without preeclampsia and compare screening performance of the International Prediction of Pregnancy Complications (IPPIC) reported models, which include various combinations of maternal factors, systolic blood pressure, diastolic blood pressure, PlGF (placental growth factor) and sFlt-1 and the competing risk (CR) models, which include various combinations of maternal factors, mean arterial pressure (MAP) and PlGF for predicting any-onset, early-onset, and late-onset preeclampsia. This was a prospective multicenter study in 7877 singleton pregnancies. The differences of the predictive performance between the IPPIC and CR models were compared. There were 141 women (1.79%) who developed preeclampsia, including 13 cases (0.17%) of early-onset preeclampsia and 128 cases (1.62%) of late-onset preeclampsia. In pregnancies that developed preeclampsia compared to unaffected pregnancies, median serum sFlt-1 levels and its MoMs were not significantly different (p>0.05). There was no significant association between gestational age at delivery and log₁₀ sFlt-1 and log₁₀ sFlt-1 MoM (p>0.05). The areas under the curve of CR models were significantly higher than the IPPIC models for the prediction of any-onset and late-onset preeclampsia but not for early-onset preeclampsia. In conclusion, there are no significant differences in the maternal serum sFlt-1 levels at 11-131 weeks' gestation between women who subsequently develop preeclampsia and those who do not. Moreover, the CR models for the prediction of any-onset and late-onset preeclampsia perform better than the IPPIC reported model.

Validation and development of models using clinical, biochemical and ultrasound markers for predicting pre-eclampsia: an individual participant data meta-analysis

BACKGROUND

Pre-eclampsia is a leading cause of maternal and perinatal mortality and morbidity. Early identification of women at risk is needed to plan management.

OBJECTIVES

To assess the performance of existing pre-eclampsia prediction models and to develop and validate models for pre-eclampsia using individual participant data meta-analysis. We also estimated the prognostic value of individual markers.

DESIGN

This was an individual participant data meta-analysis of cohort studies.

SETTING

Source data from secondary and tertiary care.

PREDICTORS

We identified predictors from systematic reviews, and prioritised for importance in an international survey.

PRIMARY OUTCOMES

Early-onset (delivery at < 34 weeks' gestation), late-onset (delivery at ≥ 34 weeks' gestation) and any-onset pre-eclampsia.

ANALYSIS

We externally validated existing prediction models in UK cohorts and reported their performance in terms of discrimination and calibration. We developed and validated 12 new models based on clinical characteristics, clinical characteristics and biochemical markers, and clinical characteristics and ultrasound markers in the first and second trimesters. We summarised the data set-specific performance of each model using a random-effects meta-analysis. Discrimination was considered promising for C-statistics of ≥ 0.7, and calibration was considered good if the slope was near 1 and calibration-in-the-large was near 0. Heterogeneity was quantified using I ² and τ². A decision curve analysis was undertaken to determine the clinical utility (net benefit) of the models. We reported the unadjusted prognostic value of individual predictors for pre-eclampsia as odds ratios with 95% confidence and prediction intervals.

RESULTS

The International Prediction of Pregnancy Complications network comprised 78 studies (3,570,993 singleton pregnancies) identified from systematic reviews of tests to predict pre-eclampsia. Twenty-four of the 131 published prediction models could be validated in 11 UK cohorts. Summary C-statistics were between 0.6 and 0.7 for most models, and calibration was generally poor owing to large between-study heterogeneity, suggesting model overfitting. The clinical utility of the models varied between showing net harm to showing minimal or no net benefit. The average discrimination for IPPIC models ranged between 0.68 and 0.83. This was highest for the second-trimester clinical characteristics and biochemical markers model to predict early-onset pre-eclampsia, and lowest for the first-trimester clinical characteristics models to predict any pre-eclampsia. Calibration performance was heterogeneous across studies. Net benefit was observed for International Prediction of Pregnancy Complications first and second-trimester clinical characteristics and clinical characteristics and biochemical markers models predicting any pre-eclampsia, when validated in singleton nulliparous women managed in the UK NHS. History of hypertension, parity, smoking, mode of conception, placental growth factor and uterine artery pulsatility index had the strongest unadjusted associations with pre-eclampsia.

LIMITATIONS

Variations in study population characteristics, type of predictors reported, too few events in some validation cohorts and the type of measurements contributed to heterogeneity in performance of the International Prediction of Pregnancy Complications models. Some published models were not validated because model predictors were unavailable in the individual participant data.

CONCLUSION

For models that could be validated, predictive performance was generally poor across data sets. Although the International Prediction of Pregnancy Complications models show good predictive performance on average, and in the singleton nulliparous population, heterogeneity in calibration performance is likely across settings.

FUTURE WORK

Recalibration of model parameters within populations may improve calibration performance. Additional strong predictors need to be identified to improve model performance and consistency. Validation, including examination of calibration heterogeneity, is required for the models we could not validate.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42015029349.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 72. See the NIHR Journals Library website for further project information.

Mean arterial pressure for predicting preeclampsia in Asian women: a longitudinal cohort study

OBJECTIVE

Previous studies suggested mean arterial pressure (MAP) had moderate predictive values in the first and second trimesters for the prediction of preeclampsia. However, the performance of MAP in Asian women is still unclear. The objective of this study was to examine the predictive values of MAP in Asian population throughout gestation, and to compare the performance of MAP, angiogenic factors and uterine artery Doppler in the prediction of preeclampsia.

DESIGN

A prospective cohort study.

SETTING

KK Women's and Children's Hospital, Singapore.

PARTICIPANTS

A total of 926 women with singleton pregnancy less than 14 weeks of gestation were included in the prospective Neonatal and Obstetrics Risks Assessment cohort between September 2010 and October 2014. Maternal blood pressure levels, uterine artery pulsatility index (UtA-PI), serum soluble fms-like tyrosine kinase 1 (sFlt-1), placental growth factor (PlGF) and sFlt-1/PlGF ratio were measured at 11-14, 18-22, 28-32 and 34 weeks onward, respectively.

PRIMARY AND SECONDARY OUTCOMES

Preeclampsia was the main pregnancy outcome.

RESULTS

A total of 20 women developed preeclampsia, who had significantly lower levels of PlGF, higher levels of sFlt-1/PlGF ratio and MAP throughout pregnancy than women without preeclampsia. Compared with angiogenic factors and UtA-PI, MAP had significantly higher area under the receiver operating characteristic curves (AUCs) for predicting preeclampsia and term preeclampsia throughout gestation. For predicting preeclampsia, MAP had AUCs of 0.86 (95% CI 0.78 to 0.95), 0.87 (95% CI 0.80 to 0.95) and 0.91 (95% CI 0.85 to 0.98) at 11-14, 18-22 and 28-32 weeks, respectively. For predicting term preeclampsia, MAP yielded AUCs of 0.87 (95% CI 0.75 to 0.99), 0.87 (95% CI 0.76 to 0.98) and 0.90 (95% CI 0.80 to 0.99) at 11-14, 18-22 and 28-32 weeks, respectively. For predicting preterm preeclampsia, the performance of MAP and PlGF was similar.

CONCLUSION

MAP is a good predictor for preeclampsia, especially term preeclampsia, in Asian women.

Epicardial adipose tissue thickness as a potential predictor of pre-eclampsia

OBJECTIVE

Pre-eclampsia (PE) is a leading cause of maternal and fetal morbidity and mortality. Our aim was to assess epicardial adipose tissue (EAT) thickness as a potential effective screening parameter to predict PE in the first trimester.

METHODS

133 women with PE were enrolled in this study, and divided into the early-onset and late-onset subgroups. 150 healthy women were enrolled as control group. Anthropometric and echocardiographic parameters were obtained, including EAT thickness. Generalized linear models was used to assess the predict efficiency of EAT with fdds ratio (OR) and 95% confidence intervals (CIs).

RESULTS

Compared to the controls, EAT thickness was higher in PE patients (P < 0.05). Multivariate regression analysis indicated that EAT thickness was associated with PE risk (OR = 1.50, 95%CI: 1.19-1.88, P < 0.05). The area under curves of EAT thickness was 0.616. When the cutoff value for EAT thickness was set to 5.26 mm, the sensitivity was 78.2% and the specificity was 44.7%. EAT thickness significantly both higher in the early-onset and late-onset groups compared to the controls; Meanwhile, EAT thickness was higher in the early-onset group than late-onset group (P < 0.05). Logistic regressionrevealed the close relationship between onset time of PE and EAT thickness (OR = 1.59, 95%CI: 1.28-1.98, P < 0.001).

CONCLUSIONS

Measured EAT thickness using echocardiography could identify high-risk people for PE as early as the first trimester. Echocardiographic EAT has the potential to be a predictor for PE prior to actual clinical diagnosis.

External validation of prognostic models predicting pre-eclampsia: individual participant data meta-analysis

BACKGROUND

Pre-eclampsia is a leading cause of maternal and perinatal mortality and morbidity. Early identification of women at risk during pregnancy is required to plan management. Although there are many published prediction models for pre-eclampsia, few have been validated in external data. Our objective was to externally validate published prediction models for pre-eclampsia using individual participant data (IPD) from UK studies, to evaluate whether any of the models can accurately predict the condition when used within the UK healthcare setting.

METHODS

IPD from 11 UK cohort studies (217,415 pregnant women) within the International Prediction of Pregnancy Complications (IPPIC) pre-eclampsia network contributed to external validation of published prediction models, identified by systematic review. Cohorts that measured all predictor variables in at least one of the identified models and reported pre-eclampsia as an outcome were included for validation. We reported the model predictive performance as discrimination (C-statistic), calibration (calibration plots, calibration slope, calibration-in-the-large), and net benefit. Performance measures were estimated separately in each available study and then, where possible, combined across studies in a random-effects meta-analysis.

RESULTS

Of 131 published models, 67 provided the full model equation and 24 could be validated in 11 UK cohorts. Most of the models showed modest discrimination with summary C-statistics between 0.6 and 0.7. The calibration of the predicted compared to observed risk was generally poor for most models with observed calibration slopes less than 1, indicating that predictions were generally too extreme, although confidence intervals were wide. There was large between-study heterogeneity in each model's calibration-in-the-large, suggesting poor calibration of the predicted overall risk across populations. In a subset of models, the net benefit of using the models to inform clinical decisions appeared small and limited to probability thresholds between 5 and 7%.

CONCLUSIONS

The evaluated models had modest predictive performance, with key limitations such as poor calibration (likely due to overfitting in the original development datasets), substantial heterogeneity, and small net benefit across settings. The evidence to support the use of these prediction models for pre-eclampsia in clinical decision-making is limited. Any models that we could not validate should be examined in terms of their predictive performance, net benefit, and heterogeneity across multiple UK settings before consideration for use in practice.

TRIAL REGISTRATION

PROSPERO ID: CRD42015029349 .

Beat-to-Beat Blood Pressure Variability in the First Trimester Is Associated With the Development of Preeclampsia in a Prospective Cohort: Relation With Aortic Stiffness

Women with preeclampsia, a hypertensive disorder of pregnancy, exhibit greater beat-to-beat blood pressure variability (BPV) in the third trimester after clinical onset of the disorder. However, it remains unknown whether elevated BPV precedes the development of preeclampsia. A prospective study cohort of 139 women (age 30.2±4.0 years) were enrolled in early pregnancy (<14 weeks gestation). BPV was quantified by time domain analyses of 10-minute continuous beat-to-beat blood pressure recordings via finger photoplethysmography in the first, second, and third trimesters. Aortic stiffness (carotid-femoral pulse wave velocity) and spontaneous cardiovagal baroreflex sensitivity were also measured each trimester. Eighteen women (13%) developed preeclampsia. Systolic BPV was higher in all trimesters among women who developed versus did not develop preeclampsia (first: 4.8±1.3 versus 3.7±1.2, P=0.001; second: 5.1±1.8 versus 3.8±1.1, P=0.02; third: 5.2±0.8 versus 4.0±1.1 mm Hg, P=0.002). Elevated first trimester systolic BPV was associated with preeclampsia (odds ratio, 1.94 [95% CI, 1.27-2.99]), even after adjusting for risk factors (age, body mass index, systolic blood pressure, history of preeclampsia, and diabetes mellitus) and was a significant predictor of preeclampsia (area under the receiver operator characteristic curve=0.75±0.07; P=0.002). Carotid-femoral pulse wave velocity was elevated in the first trimester among women who developed preeclampsia (5.9±0.8 versus 5.2±0.8 m/s; P=0.002) and was associated with BPV after adjustment for mean blood pressure (r=0.26; P=0.005). First trimester baroreflex sensitivity did not differ between groups (P=0.23) and was not related to BPV (P=0.36). Elevated systolic BPV is independently associated with the development of preeclampsia as early as the first trimester, possibly mediated in part by higher aortic stiffness.

Systematic review of prediction models for gestational hypertension and preeclampsia

INTRODUCTION

Prediction models for gestational hypertension and preeclampsia have been developed with data and assumptions from developed countries. Their suitability and application for low resource settings have not been tested. This review aimed to identify and assess the methodological quality of prediction models for gestational hypertension and pre-eclampsia with reference to their application in low resource settings.

METHODS

Using combinations of keywords for gestational hypertension, preeclampsia and prediction models seven databases were searched to identify prediction models developed with maternal data obtained before 20 weeks of pregnancy and including at least three predictors (Prospero registration CRD 42017078786). Prediction model characteristics and performance measures were extracted using the CHARMS, STROBE and TRIPOD checklists. The National Institute of Health quality assessment tools for observational cohort and cross-sectional studies were used for study quality appraisal.

RESULTS

We retrieved 8,309 articles out of which 40 articles were eligible for review. Seventy-seven percent of all the prediction models combined biomarkers with maternal clinical characteristics. Biomarkers used as predictors in most models were pregnancy associated plasma protein-A (PAPP-A) and placental growth factor (PlGF). Only five studies were conducted in a low-and middle income country.

CONCLUSIONS

Most of the studies evaluated did not completely follow the CHARMS, TRIPOD and STROBE guidelines in prediction model development and reporting. Adherence to these guidelines will improve prediction modelling studies and subsequent application of prediction models in clinical practice. Prediction models using maternal characteristics, with good discrimination and calibration, should be externally validated for use in low and middle income countries where biomarker assays are not routinely available.

Concordance-analysis and evaluation of different diagnostic algorithms used in first trimester screening for late-onset preeclampsia

Objective: Concordance-analysis and evaluation of existing algorithms detecting late-onset preeclampsia during first trimester screeningMethods: Retrospective cohort study investigating risk algorithms of late-onset preeclampsia during first trimester screening in a German prenatal center. Three previously developed algorithms including anamnestic factors (Apriori) and biophysical markers (BioM) were investigated by using detection rates (DR) with fixed FPR 10% and fixed cutoff >1:100. Furthermore, we set up a concordance-analysis of test results in late-onset preeclampsia cases to examine the effect of influencing factors and to detect potential weaknesses of the algorithms. Therefore, we modeled the probability of discordances as a function of the influencing factors based on a logistic regression, that was fitted using a Bayesian approach.Results: 6,113 pregnancies were considered, whereof 700 have been excluded and 5,413 pregnancies were analyzed. 98 (1.8%) patients developed preeclampsia (79 late-onsets, 19 early-onsets). The Apriori-algorithm reaches a DR of 34.2%, by adding BioM (MAP and UtA-PI) the DR improves to 57.0% (FPR of 10%). In concordance-analysis of Apriori algorithm and Apriori+BioM algorithms, influencing factor BMI<25 increases the chance of discordances sigificantly. Additional, in the subgroup of late-onset preeclampsias with BMI<25 the DR is higher in Apriori+BioM algorithms than in Apriori algorithm alone. If both compared algorithms include BioM, influencing factor MAP decreases the chance of discordances significantly. All other tested influencing factors do not have a statistically significant effect on discordancesConclusion: Normal-weight patients benefit more from the integration of MAP and UtA-PI compared to overweight/obese patients.

Impact of educational preeclampsia prevention booklet on knowledge and adherence to low dose aspirin among pregnant women with high risk for preeclampsia

Background Postpartum bleeding and pregnancy induced hypertension - including preeclampsia - remain to be a great cause of maternal mortality. The use of aspirin for preventing preeclampsia has been practiced recently by fetomaternal specialists in Indonesia. This study aimed to analyze the impact of education using an aspirin booklet provided by pharmacists on knowledge and adherence in taking aspirin among pregnant women with high risk for preeclampsia. Methods This was one group of pretest-posttest study. We enrolled all pregnant women with high risk for preeclampsia screened at 11+0-13+6 weeks' gestation at Fetomaternal Clinic, Dr. Ramelan Naval Hospital, Surabaya. All subjects prescribed with low-dose aspirin (100 mg) for preeclampsia prevention received oral and written education using the aspirin booklet and had been followed up for 2 months. Knowledge about aspirin for preeclampsia prevention was measured by a validated questionnaire developed for this study. Adherence to aspirin was measured by pill count method. Results A total of 12 pregnant women with high risk for preeclampsia were included during the study period. This study showed a statistically significant difference on knowledge of preeclampsia prevention before and after receiving oral and written education using aspirin booklet (p-value = 0.020), as well as aspirin adherence (p-value = 0.011). Conclusion The use of oral education and written aspirin booklet provided by pharmacists had impact on knowledge of preeclampsia prevention and adherence in taking aspirin among pregnant women with high risk for preeclampsia. We recommend to conduct randomized control study of adequate number of subjects.

Mean arterial blood pressure: potential predictive tool for preeclampsia in a cohort of healthy nulliparous pregnant women

Background

Prediction of preeclampsia is a challenge to overcome. The vast majority of prospective studies in large general obstetric populations have failed in the purpose of obtain a useful and effective model of prediction, sometimes based on complex tools unavaible in areas where the incidence of preeclampsia is the highest. The goal of this study was to assess mean arterial blood pressure (MAP) levels at 19–21, 27–29 and 37–39 weeks of gestation and performance of screening by MAP for the prediction of preeclampsia in a Brazilian cohort of healthy nulliparous pregnant women.

Methods

This was a cohort approach to a secondary analysis of the Preterm SAMBA study. Mean arterial blood pressure was evaluated at three different time periods during pregnancy. Groups with early-onset preeclampsia, late-onset preeclampsia and normotension were compared. Increments in mean arterial blood pressure between 20 and 27 weeks and 20 and 37 weeks of gestation were also calculated for the three groups studied. The accuracy of mean arterial blood pressure in the prediction of preeclampsia was determined by ROC curves.

Results

Of the 1373 participants enrolled, complete data were available for 1165. The incidence of preeclampsia was 7.5%. Women with early-onset preeclampsia had higher mean arterial blood pressure levels at 20 weeks of gestation, compared to the normotensive group. Women with late-onset preeclampsia had higher mean arterial blood pressure levels at 37 weeks of gestation, than the normotensive groups and higher increases in this marker between 20 and 37 weeks of gestation. Based on ROC curves, the predictive performance of mean arterial blood pressure was higher at 37 weeks of gestation, with an area under the curve of 0.771.

Conclusion

As an isolated marker for the prediction of preeclampsia, the performance of mean arterial blood pressure was low in a healthy nulliparous pregnant women group. Considering that early-onset preeclampsia cases had higher mean arterial blood pressure levels at 20 weeks of gestation, future studies with larger cohorts that combine multiple markers are needed for the development of a preeclampsia prediction model.

First Trimester Mean Arterial Pressure Measured Manually Versus Using an Automated Device and the Prediction of Preeclampsia: A Case-Cohort Study

OBJECTIVE

First trimester mean arterial blood pressure (MAP) can be used to predict preeclampsia. This study aimed to compare the performance of first trimester MAP measured with an automated device using a standardized technique versus MAP taken manually in a typical clinical setting.

METHODS

A case-cohort study niched into a prospective cohort of pregnant women recruited at 11-14 weeks was performed. MAP was measured with an automated device on both arms until stability was reached. These results were compared with the MAP measured with a manual device at the closest medical visit (between 10 and 15 weeks gestation) and noted in the medical charts. Receiver-operator characteristics curve analyses were used to estimate the predictive values of MAP measured by both techniques.

RESULTS

Forty-one women with preeclampsia and 167 control patients were used for the comparisons. MAP measured with an automated device decreased significantly between 11 and 14 weeks gestation (P < 0.001). Moreover, MAP measured with an automated device was a better predictor of preeclampsia (area under the curve 0.70; 95% confidence interval 0.61-0.79) than MAP measured with a manual device in a clinical setting (area under the curve 0.60; 95% confidence interval 0.50-0.70). Taken alone, MAP measured with an automated device was associated with a detection rate of preeclampsia of 34%, for a false-positive rate of 10%.

CONCLUSION

First trimester MAP can predict preeclampsia. This study demonstrated that MAP measured with an automated device using a standardized technique is a better predictor than MAP measured with a manual device.

Pilot Interventional Study Comparing Fetomaternal Outcomes of 150 mg Versus 75 mg Aspirin Starting Between 11 and 14 Weeks of Pregnancy in Patients with High Risk of Preeclampsia: A Randomized Control Trial

Introduction

Hypertensive disorders of pregnancies complicate around 5-10% of pregnancies worldwide, and together they are a member of the deadly triad along with haemorrhage and infection that contribute to a significant amount of maternal morbidity and mortality.

Aims and Objectives

To compare differences in the fetomaternal outcomes with the use of 150 mg aspirin versus 75 mg aspirin in pregnant women found to be at high risk of PE.

Methodology

This was a two-armed double-blind parallel randomized control trial conducted in the Department of Obstetrics and Gynaecology, King George's Medical University, carried over a period of 1 year.

Results

Preeclampsia occurred in 15 of 87 participants (17%) in the 75 mg aspirin group compared with 6 of 91 (6.5%) in the 150 mg aspirin group. There were a significantly higher incidence of PE, its severity and lesser period of gestation at delivery in the group given 75 mg dose compared to the group given 150 mg dose. There were significantly higher values of mean arterial pressure and uterine artery PI in women who developed preeclampsia compared to those who do not in both the groups. Foetal outcomes were observed in both the groups of women, and there was no statistically significant difference between them.

Conclusion

This randomized trial showed that among women with singleton pregnancies who were identified by means of first-trimester screening as being at high risk of preterm preeclampsia, use of aspirin 150 mg per day started between 11 and 14 weeks till 36 weeks is a potent intervention to reduce the development of both early- and late-onset preeclampsia as compared to a dose of 75 mg per day.

The International Federation of Gynecology and Obstetrics (FIGO) initiative on pre-eclampsia: A pragmatic guide for first-trimester screening and prevention

Pre‐eclampsia (PE) is a multisystem disorder that typically affects 2%–5% of pregnant women and is one of the leading causes of maternal and perinatal morbidity and mortality, especially when the condition is of early onset. Globally, 76 000 women and 500 000 babies die each year from this disorder. Furthermore, women in low‐resource countries are at a higher risk of developing PE compared with those in high‐resource countries. Although a complete understanding of the pathogenesis of PE remains unclear, the current theory suggests a two‐stage process. The first stage is caused by shallow invasion of the trophoblast, resulting in inadequate remodeling of the spiral arteries. This is presumed to lead to the second stage, which involves the maternal response to endothelial dysfunction and imbalance between angiogenic and antiangiogenic factors, resulting in the clinical features of the disorder. Accurate prediction and uniform prevention continue to elude us. The quest to effectively predict PE in the first trimester of pregnancy is fueled by the desire to identify women who are at high risk of developing PE, so that necessary measures can be initiated early enough to improve placentation and thus prevent or at least reduce the frequency of its occurrence. Furthermore, identification of an “at risk” group will allow tailored prenatal surveillance to anticipate and recognize the onset of the clinical syndrome and manage it promptly. PE has been previously defined as the onset of hypertension accompanied by significant proteinuria after 20 weeks of gestation. Recently, the definition of PE has been broadened. Now the internationally agreed definition of PE is the one proposed by the International Society for the Study of Hypertension in Pregnancy (ISSHP). According to the ISSHP, PE is defined as systolic blood pressure at ≥140 mm Hg and/or diastolic blood pressure at ≥90 mm Hg on at least two occasions measured 4 hours apart in previously normotensive women and is accompanied by one or more of the following new‐onset conditions at or after 20 weeks of gestation: 1.Proteinuria (i.e. ≥30 mg/mol protein:creatinine ratio; ≥300 mg/24 hour; or ≥2 + dipstick); 2.Evidence of other maternal organ dysfunction, including: acute kidney injury (creatinine ≥90 μmol/L; 1 mg/dL); liver involvement (elevated transaminases, e.g. alanine aminotransferase or aspartate aminotransferase >40 IU/L) with or without right upper quadrant or epigastric abdominal pain; neurological complications (e.g. eclampsia, altered mental status, blindness, stroke, clonus, severe headaches, and persistent visual scotomata); or hematological complications (thrombocytopenia–platelet count <150 000/μL, disseminated intravascular coagulation, hemolysis); or 3.Uteroplacental dysfunction (such as fetal growth restriction, abnormal umbilical artery Doppler waveform analysis, or stillbirth). It is well established that a number of maternal risk factors are associated with the development of PE: advanced maternal age; nulliparity; previous history of PE; short and long interpregnancy interval; use of assisted reproductive technologies; family history of PE; obesity; Afro‐Caribbean and South Asian racial origin; co‐morbid medical conditions including hyperglycemia in pregnancy; pre‐existing chronic hypertension; renal disease; and autoimmune diseases, such as systemic lupus erythematosus and antiphospholipid syndrome. These risk factors have been described by various professional organizations for the identification of women at risk of PE; however, this approach to screening is inadequate for effective prediction of PE. PE can be subclassified into: 1.Early‐onset PE (with delivery at <34+0 weeks of gestation); 2.Preterm PE (with delivery at <37+0 weeks of gestation); 3.Late‐onset PE (with delivery at ≥34+0 weeks of gestation); 4.Term PE (with delivery at ≥37+0 weeks of gestation). These subclassifications are not mutually exclusive. Early‐onset PE is associated with a much higher risk of short‐ and long‐term maternal and perinatal morbidity and mortality. Obstetricians managing women with preterm PE are faced with the challenge of balancing the need to achieve fetal maturation in utero with the risks to the mother and fetus of continuing the pregnancy longer. These risks include progression to eclampsia, development of placental abruption and HELLP (hemolysis, elevated liver enzyme, low platelet) syndrome. On the other hand, preterm delivery is associated with higher infant mortality rates and increased morbidity resulting from small for gestational age (SGA), thrombocytopenia, bronchopulmonary dysplasia, cerebral palsy, and an increased risk of various chronic diseases in adult life, particularly type 2 diabetes, cardiovascular disease, and obesity. Women who have experienced PE may also face additional health problems in later life, as the condition is associated with an increased risk of death from future cardiovascular disease, hypertension, stroke, renal impairment, metabolic syndrome, and diabetes. The life expectancy of women who developed preterm PE is reduced on average by 10 years. There is also significant impact on the infants in the long term, such as increased risks of insulin resistance, diabetes mellitus, coronary artery disease, and hypertension in infants born to pre‐eclamptic women. The International Federation of Gynecology and Obstetrics (FIGO) brought together international experts to discuss and evaluate current knowledge on PE and develop a document to frame the issues and suggest key actions to address the health burden posed by PE. FIGO's objectives, as outlined in this document, are: (1) To raise awareness of the links between PE and poor maternal and perinatal outcomes, as well as to the future health risks to mother and offspring, and demand a clearly defined global health agenda to tackle this issue; and (2) To create a consensus document that provides guidance for the first‐trimester screening and prevention of preterm PE, and to disseminate and encourage its use. Based on high‐quality evidence, the document outlines current global standards for the first‐trimester screening and prevention of preterm PE, which is in line with FIGO good clinical practice advice on first trimester screening and prevention of pre‐eclampsia in singleton pregnancy.1 It provides both the best and the most pragmatic recommendations according to the level of acceptability, feasibility, and ease of implementation that have the potential to produce the most significant impact in different resource settings. Suggestions are provided for a variety of different regional and resource settings based on their financial, human, and infrastructure resources, as well as for research priorities to bridge the current knowledge and evidence gap. To deal with the issue of PE, FIGO recommends the following: Public health focus: There should be greater international attention given to PE and to the links between maternal health and noncommunicable diseases (NCDs) on the Sustainable Developmental Goals agenda. Public health measures to increase awareness, access, affordability, and acceptance of preconception counselling, and prenatal and postnatal services for women of reproductive age should be prioritized. Greater efforts are required to raise awareness of the benefits of early prenatal visits targeted at reproductive‐aged women, particularly in low‐resource countries. Universal screening: All pregnant women should be screened for preterm PE during early pregnancy by the first‐trimester combined test with maternal risk factors and biomarkers as a one‐step procedure. The risk calculator is available free of charge at https://fetalmedicine.org/research/assess/preeclampsia. FIGO encourages all countries and its member associations to adopt and promote strategies to ensure this. The best combined test is one that includes maternal risk factors, measurements of mean arterial pressure (MAP), serum placental growth factor (PLGF), and uterine artery pulsatility index (UTPI). Where it is not possible to measure PLGF and/or UTPI, the baseline screening test should be a combination of maternal risk factors with MAP, and not maternal risk factors alone. If maternal serum pregnancy‐associated plasma protein A (PAPP‐A) is measured for routine first‐trimester screening for fetal aneuploidies, the result can be included for PE risk assessment. Variations to the full combined test would lead to a reduction in the performance screening. A woman is considered high risk when the risk is 1 in 100 or more based on the first‐trimester combined test with maternal risk factors, MAP, PLGF, and UTPI. Contingent screening: Where resources are limited, routine screening for preterm PE by maternal factors and MAP in all pregnancies and reserving measurements of PLGF and UTPI for a subgroup of the population (selected on the basis of the risk derived from screening by maternal factors and MAP) can be considered. Prophylactic measures: Following first‐trimester screening for preterm PE, women identified at high risk should receive aspirin prophylaxis commencing at 11–14+6 weeks of gestation at a dose of ~150 mg to be taken every night until 36 weeks of gestation, when delivery occurs, or when PE is diagnosed. Low‐dose aspirin should not be prescribed to all pregnant women. In women with low calcium intake (<800 mg/d), either calcium replacement (≤1 g elemental calcium/d) or calcium supplementation (1.5–2 g elemental calcium/d) may reduce the burden of both early‐ and late‐onset PE.

External validation of prognostic models for preeclampsia in a Dutch multicenter prospective cohort

OBJECTIVE

To perform an external validation of all published prognostic models for first-trimester prediction of the risk of developing preeclampsia (PE).

METHODS

Women <14 weeks of pregnancy were recruited in the Netherlands. All systematically identified prognostic models for PE that contained predictors commonly available were eligible for external validation.

RESULTS

3,736 women were included; 87 (2.3%) developed PE. Calibration was poor due to overestimation. Discrimination of 9 models for LO-PE ranged from 0.58 to 0.71 and of 9 models for all PE from 0.55 to 0.75.

CONCLUSION

Only a few easily applicable prognostic models for all PE showed discrimination above 0.70, which is considered an acceptable performance.

Prediction models for preeclampsia: A systematic review

BACKGROUND

Preeclampsia is a disease specific to pregnancy that can cause severe maternal and foetal morbidity and mortality. Early identification of women at higher risk for preeclampsia could potentially aid early prevention and treatment. Although a plethora of preeclampsia prediction models have been developed in recent years, individualised prediction of preeclampsia is rarely used in clinical practice.

OBJECTIVES

The objective of this systematic review was to provide an overview of studies on preeclampsia prediction.

STUDY DESIGN

Relevant research papers were identified through a MEDLINE search up to 1 January 2017. Prognostic studies on the prediction of preeclampsia or preeclampsia-related disorders were included. Quality screening was performed with the Quality in Prognostic Studies (QUIPS) tool.

RESULTS

Sixty-eight prediction models from 70 studies with 425,125 participants were selected for further review. The number of participants varied and the gestational age at prediction varied widely across studies. The most frequently used predictors were medical history, body mass index, blood pressure, parity, uterine artery pulsatility index, and maternal age. The type of predictor (maternal characteristics, ultrasound markers and/or biomarkers) was not clearly associated with model discrimination. Few prediction studies were internally (4%) or externally (6%) validated.

CONCLUSIONS

To date, multiple and widely varying models for preeclampsia prediction have been developed, some yielding promising results. The high degree of between-study heterogeneity impedes selection of the best model, or an aggregated analysis of prognostic models. Before multivariable preeclampsia prediction can be clinically implemented universally, further validation and calibration of well-performing prediction models is needed.

The ability of thromboelastography parameters to predict severe pre-eclampsia when measured during early pregnancy

OBJECTIVE

To examine the predictive value of thromboelastography parameters during early pregnancy as potential markers of severe pre-eclampsia during late pregnancy.

METHODS

An observational retrospective case-control study was conducted among pregnant women who attended a single hospital in Shanghai, China, between July 1, 2016, and February 31, 2018. Data were obtained from medical records and a structured questionnaire completed by the participants. Thromboelastography parameters included time r; time k; α angle; maximum amplitude; clot lysis at 60 minutes; and coagulation index. Other risk factors for severe pre-eclampsia were also assessed.

RESULTS

The pre-eclampsia and control groups comprised 46 and 138 women, respectively. Women with a coagulation index below zero at 13-20 weeks experienced an increased risk of severe pre-eclampsia (odds ratio [OR] 31.72, 95% confidence interval [CI] 11.28-89.24; P<0.001). Other risk factors for severe pre-eclampsia were family history of hypertension (OR 3.79, 95% CI 1.21-11.48; P=0.017) and pre-pregnancy body mass index (OR 2.83, 95% CI 1.14-7.36; P=0.023).

CONCLUSION

Coagulation index determined by thromboelastography was an early marker for severe pre-eclampsia.

Association between fetal fraction on cell-free DNA testing and first-trimester markers for pre-eclampsia

OBJECTIVES

To evaluate the association between fetal fraction on cell-free DNA (cfDNA) testing and first-trimester markers for pre-eclampsia, and to investigate the possible association of low fetal fraction with increased risks for pre-eclampsia (PE) and fetal growth restriction (FGR).

METHODS

This was a retrospective cohort study including all women with a singleton pregnancy who had risk calculation for PE and FGR between 11 + 0 and 13 + 6 weeks' gestation and who also had cfDNA as a primary or secondary screening test for chromosomal abnormalities at any gestational age at two fetal medicine clinics in Sydney and Melbourne, Australia, between March 2013 and May 2017. Logarithmically transformed fetal fraction results were adjusted for gestational age and maternal characteristics. Associations with mean arterial pressure (MAP), mean uterine artery pulsatility index (UtA-PI), pregnancy-associated plasma protein A (PAPP-A), placental growth factor (PlGF), and risks for PE < 34 weeks, PE < 37 weeks and FGR < 37 weeks were analyzed using correlation analysis and univariable and multivariable linear regressions.

RESULTS

In total, 4317 singleton pregnancies that underwent cfDNA testing with fetal fraction reported were included. Significant prediction of fetal fraction was provided by gestational age, conception by in-vitro fertilization, maternal age, body mass index, chronic hypertension, diabetes mellitus, South Asian ethnicity and being parous without history of PE or FGR. Fetal fraction was associated inversely with MAP and UtA-PI and associated positively with PAPP-A and PlGF. The lower the fetal fraction, the higher were the risks for PE < 34 weeks, PE < 37 weeks and FGR < 37 weeks (P < 0.001 for all).

CONCLUSIONS

There is a significant association between fetal fraction result and first-trimester markers for adverse pregnancy outcome. Low fetal fraction is associated with an increased risk for pregnancy complication, but its capacity to act an as independent first-trimester marker in an algorithm for screening for PE and FGR requires further research. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

The Use of Biochemical and Biophysical Markers in Early Screening for Preeclampsia in Mongolia

Preeclampsia (PE) is a major cause of maternal and perinatal morbidity and mortality, particularly in developing countries. In Mongolia, preeclampsia and eclampsia have occurred among pregnancy complications at a rate of 25% in recent years. Recent studies in the literature have screened for preeclampsia by combining maternal factors with biomarkers. This study was conducted using prospective cohort research including 393 singleton pregnancies at 11–13⁺⁶ weeks. Maternal plasmas pregnancy-associated plasma protein-A (PAPP-A) and maternal serum placental growth factor (PlGF) were measured using Perkin Elmer time-resolved fluoroimmunoassay (DELFIA) kits, and the measurement of mean arterial pressure (MAP) was performed by automated devices and the uterine artery pulsatility index was measured by Doppler ultrasound. In the study population, there were 16.7% showing complicated preeclampsia. The receiver-operating characteristics (ROC) curve analysis showed a sensitivity of 71.21%, and a specificity of 75.54% when the mean arterial pressure cut-off was 89.5 mm; while a sensitivity of 33.36% and specificity of 77.68% were observed when the uterine artery mean pulsatility index (mPI) cut-off was 2.34; a sensitivity of 79.66% and specificity of 44.04% were observed when the PAPP-A cut-off was 529.1 mU/L; and a sensitivity of 74.58% and specificity of 46.6% were observed when the PlGF cut-off was 39.87 pg/mL. The detection rates following the combination of markers with the maternal history were as follows: 62.7% with mean arterial pressure, 69.5–82.9% with two markers 86.5% with three markers and 91.4% with four markers. In conclusion, the mean arterial pressure was highly sensitive and demonstrated its easy usage and cost-effectiveness as a predictive marker for the early screening of preeclampsia from other biomarkers.

External Validation and Clinical Usefulness of First Trimester Prediction Models for the Risk of Preeclampsia: A Prospective Cohort Study

INTRODUCTION

This study assessed the external validity of all published first trimester prediction models for the risk of preeclampsia (PE) based on routinely collected maternal predictors. Moreover, the potential utility of the best-performing models in clinical practice was evaluated.

MATERIAL AND METHODS

Ten prediction models were systematically selected from the literature. We performed a multicenter prospective cohort study in the Netherlands between July 1, 2013, and December 31, 2015. Eligible pregnant women completed a web-based questionnaire before 16 weeks' gestation. The outcome PE was established using postpartum questionnaires and medical records. Predictive performance of each model was assessed by means of discrimination (c-statistic) and a calibration plot. Clinical usefulness was evaluated by means of decision curve analysis and by calculating the potential impact at different risk thresholds.

RESULTS

The validation cohort contained 2,614 women of whom 76 developed PE (2.9%). Five models showed moderate discriminative performance with c-statistics ranging from 0.73 to 0.77. Adequate calibration was obtained after refitting. The best models were clinically useful over a small range of predicted probabilities.

DISCUSSION

Five of the ten included first trimester prediction models for PE showed moderate predictive performance. The best models may provide more benefit compared to risk selection as used in current guidelines.

Preeclampsia biomarkers: An assessment of maternal cardiometabolic health

Preeclampsia is a serious pregnancy condition defined as new-onset hypertension and proteinuria, commonly characterized as either early, 'placental', or late onset, 'maternal', using a cut-off of 34 weeks gestation. However, it may be more useful to differentiate between the vascular remodelling and placental invasion vs. inflammation and metabolic pathophysiology that underlie these forms of preeclampsia. Due to rising rates of obesity, the late-onset, maternal form is increasingly occurring earlier in pregnancy. Predictive tests for preeclampsia typically include biophysical markers such as maternal body mass index and mean arterial pressure, indicating the importance of cardiovascular and metabolic health in its pathophysiology. In contrast, the placental, inflammatory, endothelial and/or metabolic biomarkers used in these tests are generally thought to indicate an abnormal response to placentation and predict the disease. However, many of these non-placental biomarkers are known to predict impaired metabolic health in non-pregnant subjects with obesity (metabolically unhealthy obesity) and coronary artery disease or stroke in people at risk for cardiovascular events. Similarities between the performance of these markers in the prediction of cardiovascular and metabolic health outside of pregnancy suggests that they may be more indicative of maternal health than predictive for preeclampsia. This paper reviews the biophysical and biochemical markers in preeclampsia prediction and compares their performance to tests assessing metabolic health and risk of cardiovascular disease, particularly in the obese population.

[Preeclampsia: A challenge also for cardiologists]

Due to its short-term consequences on perinatal outcome, preeclampsia has been long regarded as an obstetrical disease, strictly confined to a management by OB/GYNs. It has been now widely accepted that preeclampsia is most a systemic inflammatory and systemic vascular disease during pregnancy and then a lifelong risk factor for subsequent cardiovascular event in women's life. The aim of this review is to propose an overview in the current state-of-art in definition, early identification and management of preeclampsia. We will also discuss the growing evidence that support that cardiologists must be fully involved in screening and prevention of preeclampsia during pregnancy and beyond in the subsequent medical follow-up of women who have experienced a preeclampsia.

First-Trimester Inflammatory Markers for Risk Evaluation of Pregnancy Hypertension

Introduction

Hypertension in pregnancy is one of the potential causes of maternal and fetal morbidity and mortality. It complicates 7-10% of pregnancies. As of today, prediction of pregnancy hypertension is not possible.

Aim and Objectives

Evaluation of pregnancy associated plasma protein-A (PAPP-A), free β-human chorionic gonadotropin, tumor necrosis factor-α (TNF-α) and interferon gamma (INF-γ) in establishing a biomarker or combination of biomarkers for the early identification of pregnancy hypertension.

Methodology

This prospective study was carried out in two phases. Phase I was a cohort study in which 2000 pregnant women were enrolled in their first trimester (11 + 0 to 13 + 6 weeks of gestation) and followed till delivery. Women who developed hypertension were compared with normotensive cohort (women who remained normotensive till term). Phase II was a case-control study. The women who were diagnosed with hypertension in phase I were cases and their controls were matched for gestational age and sample storage time from normotensive cohort population. Two additional proinflammatory markers TNF-α and INF-γ were evaluated in this case-control population.

Results

Out of 2000 women, 199 women developed hypertension and 1454 women remained normotensive throughout their pregnancy. Among 199 hypertensive women, 151 (9.13%) cases had gestational hypertension, 45 (2.72%) had preeclampsia (PE) and 3 (0.18%) had eclampsia (E). First trimester mean arterial pressure (MAP) (p < 0.001) and body mass index (BMI) (p < 0.001) were found significantly higher in hypertensive women when compared with normotensive women. Maternal serum levels of PAPP-A (p < 0.001) were significantly low in hypertensive women as compared to normotensive women, while free β-hCG (p = 0.59) was high, but the difference was not statistically significant. TNF-α (p < 0.001) and INF-γ (p = 0.014) both were high in hypertensive women. When all biomarkers were combined we found the positive predictive value (PPV) of 51.6% an negative predictive value (NPV) of 71.4%.

Conclusion

Increased levels of proinflammatory cytokines suggest the role of underlying inflammation in pathogenesis of pregnancy hypertension, and low PAPP-A may be attributed to impaired implantation. Combining biomarkers may improve the prediction of pregnancy hypertension in the early stages of gestation. NPV of 71.4% depicts that if woman has all biomarkers in normal ranges during first trimester, she will have 71.4% chances of remaining normotensive during pregnancy.

First-trimester mean arterial blood pressure and the risk of preeclampsia: The Great Obstetrical Syndromes (GOS) study

OBJECTIVE

To estimate the predictive value of first-trimester mean arterial pressure (MAP) for the hypertensive disorders of pregnancy (HDP).

STUDY METHODS

We performed a prospective cohort study of nulliparous women recruited at 11^0/7-13^6/7 weeks. MAP was calculated from blood pressure measured on both arms simultaneously using an automated device taking a series of recordings until blood pressure stability was reached. MAP was reported as multiples of the median adjusted for gestational age. Participants were followed for development of gestational hypertension (GH), preeclampsia (PE), preterm PE (<37 weeks) and early-onset (EO) PE (<34 weeks). Receiver operating characteristic curves and the area under the curve (AUC) were used to estimate the predictive values of MAP. Multivariate logistic regressions were used to develop predictive models combining MAP and maternal characteristics.

RESULTS

We obtained complete follow-up in 4700 (99%) out of 4749 eligible participants. GH without PE was observed in 250 (5.3%) participants, and PE in 241 (5.1%), including 33 (0.7%) preterm PE and 10 (0.2%) EO-PE. First-trimester MAP was associated with GH (AUC: 0.77; 95%CI: 0.74-0.80); term PE (0.73; 95%CI: 0.70-0.76), preterm PE (0.80; 95%CI: 0.73-0.87) and EO-PE (0.79; 95%CI: 0.62-0.96). At a 10% false-positive rate, first-trimester MAP could have predicted 39% of GH, 34% of term PE, 48% of preterm PE and 60% of EO-PE. The addition of maternal characteristics improved the predictive values (to 40%, 37%, 55% and 70%, respectively).

CONCLUSION

First-trimester MAP is a strong predictor of GH and PE in nulliparous women.

Simple approach based on maternal characteristics and mean arterial pressure for the prediction of preeclampsia in the first trimester of pregnancy

AIM

To propose a simple model for predicting preeclampsia (PE) in the 1st trimester of pregnancy on the basis of maternal characteristics (MC) and mean arterial pressure (MAP).

METHODS

A prospective cohort was performed to predict PE between 11 and 13+6 weeks of gestation. The MC evaluated were maternal age, skin color, parity, previous PE, smoking, family history of PE, hypertension, diabetes mellitus and body mass index (BMI). Mean arterial blood pressure (MAP) was measured at the time of the 1st trimester ultrasound. The outcome measures were the incidences of total PE, preterm PE (delivery <37 weeks) and term PE (delivery ≥37 weeks). We performed logistic regression analysis to determine which factors made significant contributions for the prediction of the three outcomes.

RESULTS

We analyzed 733 pregnant women; 55 developed PE, 21 of those developed preterm PE and 34 term PE. For total PE, the best model was MC+MAP, which had an area under the receiver operating characteristic curve (AUC ROC) of 0.79 [95% confidence interval (CI)=0.76-0.82]. For preterm PE, the best model was MC+MAP, with an AUC ROC of 0.84 (95% CI=0.81-0.87). For term PE, the best model was MC, with an AUC ROC of 0.75 (0.72-0.79). The MC+MAP model demonstrated a detection rate of 67% cases of preterm PE, with a false-positive rate of 10%, positive predictive value of 17% and negative predictive value of 99%.

CONCLUSION

The MC+MAP model showed good accuracy in predicting preterm PE in the 1st trimester of gestation.

Impaired placentation in women with chronic hypertension who develop pre-eclampsia

OBJECTIVE

To compare the degree of impaired placentation in women with and those without chronic hypertension (CH) who develop pre-eclampsia (PE) in pregnancy.

METHODS

Data were derived from prospective screening for adverse pregnancy outcomes in women with singleton pregnancy attending their first routine hospital visit at 11 + 0 to 13 + 6 weeks' gestation. This visit included recording of maternal characteristics and medical history and measurement of mean arterial pressure (MAP), uterine artery pulsatility index (UtA-PI), serum placental growth factor (PlGF) and serum pregnancy-associated plasma protein-A (PAPP-A). The measured biomarkers were converted to multiples of the median (MoM) after adjustment for pregnancy characteristics. MoM values in women with CH who developed PE (n = 283) were compared to those of women without CH who developed PE (n = 2236).

RESULTS

In both groups with and without CH, measurements of MAP and UtA-PI were increased, whereas those of PlGF and PAPP-A were decreased and the deviation from normal in all biomarkers decreased with advancing gestational age at delivery with PE. There was no significant difference between women with and those without CH in the slope of the regression line of log₁₀ MoM biomarker values against gestational age at delivery with PE for any of the biomarkers. However, there was a significant difference in the intercepts and coefficients of biomarkers in the two groups; compared to those without CH, MAP MoM, PlGF MoM and PAPP-A MoM were higher and UtA-PI MoM was lower in the CH group (all P < 0.01).

CONCLUSION

In pregnancies that develop PE, the degree of impaired placentation, reflected in high UtA-PI and low PlGF and PAPP-A at 11-13 weeks' gestation, is less in women with CH than in those without CH. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Validation of Fetal Medicine Foundation algorithm for prediction of pre-eclampsia in the first trimester in an unselected Brazilian population

OBJECTIVE

The objective of this study is to evaluate the predictive performance of the Fetal Medicine Foundation (FMF) algorithm for prediction of preeclampsia (PE) between 11 and 14 weeks of gestation in an unselected Brazilian population.

METHODS

We conducted a prospective cohort study with 617 singleton pregnancies of unselected risk. Biophysical markers (mean pulsatility index, mean arterial pressure) and biochemical markers (placental growth factor (PLGF) and PAPP-A) were inserted into the FMF software and converted into multiples of the median (MoM). The subjects were divided into five groups: early-onset PE, parturition <34 weeks' gestation; preterm PE, parturition <37 weeks; PE, parturition at any gestational age; gestational hypertension (GH); and control group. Areas under the receiver operating characteristics curve (AUC) were calculated for the outcomes.

RESULTS

Among 617 patients, seven developed early-onset PE, 18 developed preterm PE (seven early PE plus 11 delivered between 34 and 36 + 6 weeks gestation), 34 developed PE (18 preterm PE plus 16 delivered after 37-week gestation), 12 pregnant women developed GH, and 517 women comprised the control group. The best predictive performance using the FMF algorithm occurred in the early-onset PE group, with AUC = 0.946 (95% CI 0.919-0.973) and the detection rate of 28.6% and 85.7% for 5% and 10% false-positive (FP), respectively.

CONCLUSIONS

The FMF algorithm to predict PE was effective in a Brazilian population, mainly in the early-onset form of the disease at 10% FP.

External validation of preexisting first trimester preeclampsia prediction models

OBJECTIVE

To validate the increasing number of prognostic models being developed for preeclampsia using our own prospective study.

STUDY DESIGN

A systematic review of literature that assessed biomarkers, uterine artery Doppler and maternal characteristics in the first trimester for the prediction of preeclampsia was performed and models selected based on predefined criteria. Validation was performed by applying the regression coefficients that were published in the different derivation studies to our cohort. We assessed the models discrimination ability and calibration.

RESULTS

Twenty models were identified for validation. The discrimination ability observed in derivation studies (Area Under the Curves) ranged from 0.70 to 0.96 when these models were validated against the validation cohort, these AUC varied importantly, ranging from 0.504 to 0.833. Comparing Area Under the Curves obtained in the derivation study to those in the validation cohort we found statistically significant differences in several studies.

CONCLUSION

There currently isn't a definitive prediction model with adequate ability to discriminate for preeclampsia, which performs as well when applied to a different population and can differentiate well between the highest and lowest risk groups within the tested population. The pre-existing large number of models limits the value of further model development and future research should be focussed on further attempts to validate existing models and assessing whether implementation of these improves patient care.

MoM cutoffs for variables, an important tool for multivariate analysis and accurate interpretation of preeclampsia risk in high-risk pregnancy at 11-13+6 weeks gestation

OBJECTIVE

To determine the diagnostic accuracy of preeclampsia (PE) screening test offered in early pregnancy for the prediction of the risks for early-onset (requiring delivery <32 weeks gestation) and late-onset (requiring delivery ≥32 weeks gestation) disease.

METHODS

In a retrospective study of 615 women with singleton pregnancy, the risk for PE was calculated by the combined effect of multiple variables: serum placental growth factor (PLGF) and pregnancy-associated plasma protein-A (PAPP-A), maternal age, parity, ethnicity, mean arterial pressure (MAP), body mass index (BMI), uterine artery-pulsatility index, and previous history of PE or hypertension (HT). The results of the screening test in three different groups of women were validated by pregnancy outcome: (i) control group - without any history of PE/HT; (ii) history of PE without HT; and (iii) history of HT without PE. The performance of the screening test was evaluated for early- and late-onset PE.

RESULTS

The multivariate screening effectively identified cases of PE with >97% specificity. The detection rate (DR) was 93.8% for late-onset PE at a false positive rate (FPR) of 2.3% and 44.4% for early-onset PE at an FPR of 0.0%. The incidence of PE was 7% overall, with 1.52% and 5.43% for early- and late-onset PE, respectively.

CONCLUSION

The study demonstrated 96.6% diagnostic accuracy of the multi-variable screening test to predict the risk of PE in the first trimester. The negative predictive value (>98%) reinforces the utility of cost-effective noninvasive screening test for the early detection of PE.

ABBREVIATIONS

PLGF: Placental growth factor; PAPP-A: Pregnancy-associated plasma protein-A; free β-HCG: Free beta-human chorionic gonadotropin; BMI: Body mass index; MAP: Mean arterial blood pressure; Ut-PI: Mean uterine artery pressure (left and right uterine artery)-pulsatility index; MoM: Multiple of median; NICE: National Institute for Health and Clinical Excellence.

Relationship between first-trimester serum placental protein-13 and maternal characteristics, placental Doppler studies and pregnancy outcome

OBJECTIVE

To examine potential correlations between maternal serum placental protein-13 (PP-13) and first trimester maternal and placental factors, and to evaluate the association of this marker with adverse pregnancy outcome.

METHODS

Serum samples from prospectively enrolled patients between 11 and 13 weeks and 6 days were analyzed for PP-13 using an ELISA assay. The relationships between maternal serum PP-13 levels and gestational age, maternal age, ethnicity, parity, smoking status, body mass index (BMI), mean arterial blood pressure, uterine and umbilical artery Doppler parameters were examined. The association between first-trimester PP-13 levels and subsequent pre-eclampsia and delivery of a small for gestational age (SGA) neonate was also investigated, after excluding patients who received aspirin.

RESULTS

In 908 patients, PP-13 levels ranged from 8.0 to 537.5 pg/mL. A significant negative correlation was identified between PP13 and BMI (Spearman rho -0.20, P<0.0001). Smoking significantly decreased PP-13 (P<0.01). No relationship was identified with the other parameters. In a subgroup of 668 low-risk patients who did not receive aspirin, PP-13 levels were not associated with development of pre-eclampsia, SGA or the combination of them.

CONCLUSION

First-trimester PP-13 levels are significantly correlated with BMI and smoking. These correlations appear independent of uterine and umbilical artery resistance. In low risk patients, PP-13 levels fail to predict the risk for pre-eclampsia or SGA.