Screening for preeclampsia in low-risk twin pregnancies at early gestation

The potential of repeated mean arterial pressure measurements for predicting early- and late-onset pre-eclampsia in twin pregnancies: Prediction model study

OBJECTIVE

To investigate the contribution of longitudinal mean arterial pressure (MAP) measurement during the first, second, and third trimesters of twin pregnancies to the prediction of pre-eclampsia.

METHODS

A retrospective cohort study was conducted on women with twin pregnancies. Historical data between 2019 and 2021 were analyzed, including maternal characteristics and mean artery pressure measurements were obtained at 11-13, 22-24, and 28-33 weeks of gestation. The outcome measures included pre-eclampsia with delivery <34 and ≥34 weeks of gestation. Models were developed using logistic regression, and predictive performance was evaluated using the area under the curve, detection rate at a given false-positive rate of 10%, and calibration plots. Internal validation was conducted via bootstrapping.

RESULTS

A total of 943 twin pregnancies, including 36 (3.82%) women who experienced early-onset pre-eclampsia and 93 (9.86%) who developed late-onset pre-eclampsia, were included in this study. To forecast pre-eclampsia during the third trimester, the most accurate prediction for early-onset pre-eclampsia resulted from a combination of maternal factors and MAP measured during this trimester. The optimal predictive model for late-onset pre-eclampsia includes maternal factors and MAP data collected during the second and third trimesters. The areas under the curve were 0.937 (95% confidence interval [CI] 0.894-0.981) and 0.887 (95% CI 0.852-0.921), respectively. The corresponding detection rates were 83.33% (95% CI 66.53%-93.04%) for early-onset pre-eclampsia and 68.82% (95% CI 58.26%-77.80%) for late-onset pre-eclampsia.

CONCLUSION

Repeated measurements of MAP during pregnancy significantly improved the accuracy of late-onset pre-eclampsia prediction in twin pregnancies. The integration of longitudinal data into pre-eclampsia screening may be an effective and valuable strategy.

Predictive value of the soluble fms-like tyrosine kinase 1 to placental growth factor ratio for preeclampsia in twin pregnancies: a systematic review and meta-analysis

OBJECTIVE

In recent years, the ratio of soluble fms-like tyrosine kinase 1 to placental growth factor for use in predicting preeclampsia has been explored extensively. Despite extensive research, available data on its effectiveness in predicting preeclampsia in twin pregnancies are limited and conflicting. This meta-analysis aimed to assess the diagnostic accuracy of the soluble fms-like tyrosine kinase 1 to placental growth factor ratio in distinguishing cases with preeclampsia in twin pregnancies from healthy controls.

DATA SOURCES

Studies that evaluated the use of the soluble fms-like tyrosine kinase 1 to placental growth factor ratio in predicting preeclampsia were searched in PubMed, Embase, and Cochrane databases from inception to August 6, 2023, without language restriction.

STUDY ELIGIBILITY CRITERIA

The following population, exposure, comparators, outcomes, and study designs were included: women with twin pregnancies; an increased soluble fms-like tyrosine kinase 1 to placental growth factor ratio with preeclampsia as the outcome; women without preeclampsia; a 2 × 2 diagnostic table, diagnostic accuracy data, and the incidence of preeclampsia; and prospective cohort studies and observational comparative studies, respectively.

STUDY APPRAISAL AND SYNTHESIS METHODS

The quality of the included studies was evaluated. Key parameters, including the specificity, sensitivity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio, were calculated using the random- and fixed-effects models. In addition, the area under the receiver operating characteristic curve and the summary receiver operating characteristic curve were evaluated.

RESULTS

A total of 7 studies were included, including 442 women with twin pregnancies (115 patients with preeclampsia and 327 controls without preeclampsia). The results highlighted the promising effectiveness of the soluble fms-like tyrosine kinase 1 to placental growth factor ratio in predicting preeclampsia in twin pregnancies with a pooled specificity of 0.89 (95% confidence interval, 0.80-0.95), a sensitivity of 0.84 (95% confidence interval, 0.73-0.93), a positive likelihood ratio of 32.76 (95% confidence interval, 12.82-83.74), and a negative likelihood ratio of 0.03 (95% confidence interval, 0.01-0.08). The combined diagnostic odds ratio was 35.72 (95% confidence interval, 12.92-98.76), and the area under the receiver operating characteristic curve was 0.92.

CONCLUSION

These collective findings underscore the potential of the soluble fms-like tyrosine kinase 1 to placental growth factor ratio as an accurate marker for identifying preeclampsia among women with twin pregnancies.

Initial establishment and validation of a predictive model for preeclampsia in twin pregnancies based on maternal characteristics and echocardiographic parameters

INTRODUCTION

The primary objective of this study was to evaluate the association between maternal echocardiographic changes and the occurrence of preeclampsia (PE) in twin pregnancies. Additionally, we established and validated a prediction model for PE in twin pregnancies.

MATERIAL AND METHODS

The first part of this study was retrospective and included data from 854 twin pregnancies that received antenatal care at Peking University Third Hospital from April 2017 to April 2021 (training cohort). Overall, 159 women who underwent transthoracic echocardiography were included in the analysis. To build a predictive model, cardiac findings were compared between normotensive women and those with PE. The model was then validated in a prospective longitudinal cohort (test cohort) that included 109 women with twin pregnancies who underwent two consecutive transthoracic echocardiography examinations during the second and third trimesters.

RESULTS

Fifty-four normotensive women and 105 women with PE were analyzed in the retrospective cohort that was used to build the model in which later preeclampsia was associated with higher left ventricular mass index (>61 g/m2 ), interventricular septal thickness (>7.87 mm), left atrial anteroposterior diameter (>33.5 mm), mitral inflow late diastolic velocity (A) (>0.685 m/s), ratio of early diastolic velocity (E) and peak early diastolic myocardial velocity of the lateral mitral annulus (>6.5), and lower peak early diastolic myocardial velocity (<13.1 cm/s). The optimized PE prediction model based on the interventricular septal thickness, left atrial anteroposterior diameter, A, peak early diastolic myocardial velocity and pre-pregnancy bodyweight index was then established (area under the curve [AUC] = 0.840, 95% CI 0.778-0.903, P < 0.001). The model was tested in the prospective cohort including 87 normotensive women and 22 women with PE; the validation test showed that the prediction model in the second (AUC = 0.801) and third (AUC = 0.811) trimesters had high discriminative ability and calibration.

CONCLUSIONS

Maternal echocardiographic changes in twin pregnancies are associated with the development of preeclampsia. The model constructed, based on the echocardiographic parameters and body mass index, provides novel ideas for the prediction of PE.

Intertwin growth discordance throughout gestation and hypertensive disorders of pregnancy

BACKGROUND

Previous studies have established the association between intertwin birthweight discordance and hypertensive disorders of pregnancy. However, longitudinal fetal size discordance concerning gestational hypertension or preeclampsia remains unclear.

OBJECTIVE

This study aimed to compare the patterns of estimated fetal weight discordance throughout gestation among normotensive women, women with gestational hypertension, and women with preeclampsia and to evaluate the association between crown-rump length discordance at 11 to 14 weeks of gestation and hypertensive disorders of pregnancy.

STUDY DESIGN

This was a retrospective cohort study of women with twin pregnancies who had antenatal care visits and delivered at a tertiary hospital between January 2013 and June 2021. The crown-rump length was measured at 11 to 14 weeks of gestation. Estimated fetal weight was calculated based on ultrasound examinations of fetal biometrics at 16 to 18, 20 to 24, 28 to 32, and ≥34 weeks of gestation, respectively. Crown-rump length and estimated fetal weight discordances were calculated: (larger crown-rump length - smaller crown-rump length)/larger crown-rump length × 100% and (larger estimated fetal weight - smaller estimated fetal weight)/larger estimated fetal weight × 100%, respectively. Multiple imputation was used to handle missing data, and all models accounted for the imputation. Multilevel model analysis was used to compare the differences in estimated fetal weight discordances throughout gestation among normotensive women, women with gestational hypertension, and women with preeclampsia. Generalized linear models were used to evaluate the association between crown-rump length discordance and hypertensive disorders of pregnancy, assuming a Poisson distribution. The possible nonlinear relationship between continuous crown-rump length discordance and hypertensive disorders of pregnancy was examined by generalized additive models. All analyses were stratified by chorionicity.

RESULTS

Of the 3280 women with twin pregnancies who met the inclusion criteria, 187 (5.7%) developed gestational hypertension, and 436 (13.3%) developed preeclampsia, including 125 (3.8%) early-onset preeclampsia and 311 (9.5%) late-onset preeclampsia. In women with dichorionic twin pregnancies, compared with normotensive women, a substantial progression of estimated fetal weight discordance throughout pregnancy was identified in women who developed preeclampsia, and a large progression of estimated fetal weight discordance in late pregnancy was identified in women who developed gestational hypertension. In women with monochorionic twin pregnancies, estimated fetal weight discordances were more progressive from 20 to 24 weeks of gestation onward in women who developed preeclampsia than in normotensive women. Crown-rump length discordance at 11 to 14 weeks of gestation was associated with an increased risk of preeclampsia (relative risk, 1.03; 95% confidence interval, 1.00-1.05), particularly early-onset preeclampsia (relative risk, 1.09; 95% confidence interval, 1.04-1.13). A crown-rump length discordance of ≥10% had 1.2 times the increased risk of developing early-onset preeclampsia (relative risk, 2.27; 95% confidence interval, 1.28-4.03). This association was identified in dichorionic twins, but not in monochorionic twins.

CONCLUSION

Our study demonstrated distinct growth discordant patterns among normotensive women, women with gestational hypertension, and women with preeclampsia in twin pregnancies. Intertwin crown-rump length discordance at 11 to 14 weeks of gestation was associated with an increased risk of preeclampsia, especially early-onset preeclampsia in dichorionic twin pregnancies, with a dose-response pattern.

Development and Validation of Multi-Stage Prediction Models for Pre-eclampsia: A Retrospective Cohort Study on Chinese Women

Objective

The aim of this study is to develop multistage prediction models for pre-eclampsia (PE) covering almost the entire pregnancy period based on routine antenatal measurements and to propose a risk screening strategy.

Methods

This was a retrospective cohort study that included 20582 singleton pregnant women with the last menstruation between January 1, 2013 and December 31, 2019. Of the 20582 women, 717 (3.48%) developed pre-eclampsia, including 46 (0.22%) with early-onset pre-eclampsia and 119 (0.58%) preterm pre-eclampsia. We randomly divided the dataset into the training set (N = 15665), the testing set (N = 3917), and the validation set (N = 1000). Least Absolute Shrinkage And Selection Operator (LASSO) was used to do variable selection from demographic characteristics, blood pressure, blood routine examination and biochemical tests. Logistic regression was used to develop prediction models at eight periods: 5-10 weeks, 11-13 weeks, 14-18 weeks, 19-23 weeks, 24-27 weeks, 28-31 weeks, 32-35 weeks, and 36-39 weeks of gestation. We calculated the AUROC (Area Under the Receiver Operating Characteristic Curve) on the test set and validated the screening strategy on the validation set.

Results

We found that uric acid tested from 5-10 weeks of gestation, platelets tested at 18-23 and 24-31 weeks of gestation, and alkaline phosphatase tested at 28-31, 32-35 and 36-39 weeks of gestation can further improve the prediction performance of models. The AUROC of the optimal prediction models on the test set gradually increased from 0.71 at 5-10 weeks to 0.80 at 24-27 weeks, and then gradually increased to 0.95 at 36-39 weeks of gestation. At sensitivity level of 0.98, our screening strategy can identify about 94.8% of women who will develop pre-eclampsia and reduce about 40% of the healthy women to be screened by 28-31 weeks of pregnancy.

Conclusion

We developed multistage prediction models and a risk screening strategy, biomarkers of which were part of routine test items and did not need extra costs. The prediction window has been advanced to 5-10 weeks, which has allowed time for aspirin intervention and other means for PE high-risk groups.

A New Model for the Predicting the Risk of Preeclampsia in Twin Pregnancy

Objective

We aimed to develop an effective nomogram model for predicting the risk of preeclampsia in twin pregnancies.

Methods

The study was a retrospective cohort study of women pregnant with twins who attended antenatal care and labored between January 2015 and December 2020 at the Fujian Maternity and Child Health Hospital, China. We extracted maternal demographic data and clinical characteristics. Then we performed the least absolute shrinkage and selection operator regression combined with clinical significance to screen variables. Thereafter, multivariate logistic regression was used to construct a nomogram that predicted the risk of preeclampsia in twin pregnancies. Finally, the nomogram was validated using C-statistics (C-index) and calibration curves.

Results

A total of 2,469 women with twin pregnancies were included, of whom 325 (13.16%) had preeclampsia. Multivariate logistic regression models revealed that serum creatinine, uric acid, mean platelet volume, high-density lipoprotein, lactate dehydrogenase, fibrinogen, primiparity, pre-pregnancy body mass index, and regular prenatal were independently associated with preeclampsia in twin pregnancies. The constructed predictive model exhibited a good discrimination and predictive ability for preeclampsia in twin pregnancies (concordance index 0.821).

Conclusion

The model for the prediction of preeclampsia in twin pregnancies has high accuracy and specificity. It can be used to assess the risk of preeclampsia 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.

Fetal growth standards for Chinese twin pregnancies

Background

The common use of singleton fetal growth standard to access twin growth might lead to over-monitoring and treatment. We aimed to develop fetal growth standards for Chinese twins based on ultrasound measurements, and compare it with Zhang’s and other twin fetal growth charts.

Methods

A cohort of uncomplicated twin pregnancies were prospectively followed in 2014–2017. Smoothed estimates of fetal growth percentiles for both monochorionic (MC) and dichorionic (DC) twins were obtained using a linear mixed model. We also created growth charts for twins using a model-based approach proposed by Zhang et al. Our twin standards were compared with Hadlock’s (singleton) in predicting adverse perinatal outcomes.

Results

A total of 398 twin pregnancies were included, with 214 MC and 582 DC live-born twins. The MC twins were slightly lighter than the DC twins, with small differences throughout the gestation. Our ultrasound-based fetal weight standards were comparable to that using Zhang’s method. Compared with previous references/standards from the US, Brazil, Italy and UK, our twins had very similar 50th percentiles, but narrower ranges between the 5th and 95th or 10th and 90th percentiles. Compared with the Hadlock’s standard, the risks of neonatal death and adverse perinatal outcomes for small for gestational age (SGA) versus non-SGA were substantially elevated using our standards.

Conclusions

A normal fetal growth standard for Chinese twins was created. The differences between MC and DC twins were clinically insignificant. The 50th weight percentiles of the Chinese twins were identical to those in other races/ethnicities but the ranges were markedly narrower. Our standard performed much better than the Hadlock’s in predicting low birth weight infants associated with adverse perinatal outcomes in twin pregnancies. The present study also indicated that Zhang’s method is applicable to Chinese twins, and other areas may use Zhang’s method to generate their own curves for twins if deemed necessary.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-03926-y.

Live birth rate of twin pregnancies after frozen embryo transfer: natural cycle versus ovulation induction regimens

PURPOSE

Ovulation induction (OI) using letrozole or human menopausal hormone (hMG) is recently developed for endometrium preparation in frozen embryo transfer (FET) cycles. The purpose of this study is to compare the live birth rate of twin pregnancies between modified natural and OI regimens for endometrium preparation in FET cycles.

STUDY DESIGN

This study included all consecutive twin pregnancies following FET with modified natural cycle (mNC-FET) or OI (OI-FET) regimen for endometrium preparation between January 2015 to June 2019. Primary outcome was the live birth of at least one twin per pregnancy. Multivariable logistic regression analysis was used to evaluate the potential association of endometrium preparation regimen and live birth. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated.

RESULTS

During the study period, 269 twin pregnancies after mNC-FET and 177 twin pregnancies after OI-FET were included. The live birth rate of at least one twin per pregnancy was not significantly different between mNC-FET and OI-FET groups, 92.2% vs 90.4%; aOR 0.65; 95%CI 0.32-1.34. The multivariable regression analysis showed that twin pregnancies after OI-FET had decreased odds for gestational diabetes mellitus (aOR 0.37; 95% CI 0.16-0.87) in comparison to twin pregnancies after mNC-FET. In subgroup analysis, we found that the rate of live birth of at least one twin per pregnancy was significantly higher in OI-FET cycles using letrozole compared to those using hMG (94% vs 83.3%; aOR 3.45; 95%CI 1.24-9.57).

CONCLUSION

The live birth rate in twin pregnancies after FET is comparable between mNC or OI regimens for endometrium preparation.