Prediction of recurrence of hypertensive disorders of pregnancy between 34 and 37 weeks of gestation: a retrospective cohort study

Common pathogenesis of early and late preeclampsia: evidence from recurrences and review of the literature

OBJECTIVE

To investigate whether there is an association between the gestational age at the onset of preeclampsia in recurrent cases and the gestational age at the onset of preeclampsia in previous pregnancies.

METHODS

This retrospective nested case-control study was designed to investigate whether gestational age at diagnosis and at delivery in recurrent cases of preeclampsia correlates with gestational age at diagnosis and delivery in the previous cases of preeclampsia in the same individuals. The database of a Ukrainian research network was used to find patients with the diagnosis of preeclampsia between 2019 and 2021. The database was further queried to identify those with a history of preeclampsia in a previous pregnancy. The comparison was made using the Pearson correlation coefficient.

RESULTS

One hundred and three patients who were diagnosed with preeclampsia were identified. Of those, 15 had recurrent preeclampsia, 2 of whom had preeclampsia in 2 previous pregnancies. There was no statistically significant correlation: based on gestational age at delivery R = - 0.28 (P = 0.30; 95% confidence interval (- 0.69 to 0.28) and based on gestational age at the time of diagnosis R = - 0.14 (P = 0.62; - 0.60 to 0.41).

CONCLUSION

Our data do not find an association between the gestational age of recurrent preeclampsia and preeclampsia diagnosed in a previous pregnancy. This supports the idea that there is single pathogenesis for preeclampsia regardless of the gestational age. It suggests that there are variations in the course of preeclampsia that may be determined by the capacity of the compensatory mechanisms.

Does Developing Interpregnancy Hypertension Affect the Recurrence Risk of Preeclampsia? A Population-Based Cohort Study

BACKGROUND

Preeclampsia in a first pregnancy is a strong risk factor for preeclampsia in a second pregnancy. Whether chronic hypertension developed after a first pregnancy (interpregnancy hypertension) affects the recurrence risk of preeclampsia is unknown.

METHODS

This is a population-based cohort study of 391,645 women with their first and second singleton births between 2006 and 2017. Exposure groups were women with preeclampsia in their first pregnancy, interpregnancy hypertension, or both risk factors. Women with neither risk factor were used as a reference group. We calculated the adjusted relative risk (aRR) with 95% confidence intervals (CIs) for overall preeclampsia in the second pregnancy as well as preterm (<37 gestational weeks) and term (≥37 gestational weeks) subgroups of the disease.

RESULTS

Women with preeclampsia in their first pregnancy who did or did not develop interpregnancy hypertension had rates of preeclampsia in their second pregnancy of 21.5% and 13.6%, respectively. In the same population, the corresponding rates of preterm preeclampsia were 5.5% and 2.6%, respectively. After adjusting for maternal factors, women with preeclampsia in their first pregnancy who developed interpregnancy hypertension and those who did not have almost the same risk of overall preeclampsia in their second pregnancy (aRRs with 95% CIs: 14.51; 11.77-17.89 and 12.83; 12.09-13.62, respectively). However, preeclampsia in the first pregnancy and interpregnancy hypertension had a synergistic interaction on the outcome of preterm preeclampsia (aRR with 95% CI 26.66; 17.44-40.80).

CONCLUSIONS

Women with previous preeclampsia who developed interpregnancy hypertension had a very high rate of preterm preeclampsia in a second pregnancy, and the two risk factors had a synergistic interaction.

Effects of race and ethnicity on perinatal outcomes in high-income and upper-middle-income countries: an individual participant data meta-analysis of 2 198 655 pregnancies

BACKGROUND

Existing evidence on the effects of race and ethnicity on pregnancy outcomes is restricted to individual studies done within specific countries and health systems. We aimed to assess the impact of race and ethnicity on perinatal outcomes in high-income and upper-middle-income countries, and to ascertain whether the magnitude of disparities, if any, varied across geographical regions.

METHODS

For this individual participant data (IPD) meta-analysis we used data from the International Prediction of Pregnancy Complications (IPPIC) Network of studies on pregnancy complications; the full dataset comprised 94 studies, 53 countries, and 4 539 640 pregnancies. We included studies that reported perinatal outcomes (neonatal death, stillbirth, preterm birth, and small-for-gestational-age babies) in at least two racial or ethnic groups (White, Black, south Asian, Hispanic, or other). For our two-step random-effects IPD meta-analysis, we did multiple imputations for confounder variables (maternal age, BMI, parity, and level of maternal education) selected with a directed acyclic graph. The primary outcomes were neonatal mortality and stillbirth. Secondary outcomes were preterm birth and a small-for-gestational-age baby. We estimated the association of race and ethnicity with perinatal outcomes using a multivariate logistic regression model and reported this association with odds ratios (ORs) and 95% CIs. We also did a subgroup analysis of studies by geographical region.

FINDINGS

51 studies from 20 high-income and upper-middle-income countries, comprising 2 198 655 pregnancies, were eligible for inclusion in this IPD meta-analysis. Neonatal death was twice as likely in babies born to Black women than in babies born to White women (OR 2·00, 95% CI 1·44-2·78), as was stillbirth (2·16, 1·46-3·19), and babies born to Black women were at increased risk of preterm birth (1·65, 1·46-1·88) and being small for gestational age (1·39, 1·13-1·72). Babies of women categorised as Hispanic had a three-times increased risk of neonatal death (OR 3·34, 95% CI 2·77-4·02) than did those born to White women, and those born to south Asian women were at increased risk of preterm birth (OR 1·26, 95% CI 1·07-1·48) and being small for gestational age (1·61, 1·32-1·95). The effects of race and ethnicity on preterm birth and small-for-gestational-age babies did not vary across regions.

INTERPRETATION

Globally, among underserved groups, babies born to Black women had consistently poorer perinatal outcomes than White women after adjusting for maternal characteristics, although the risks varied for other groups. The effects of race and ethnicity on adverse perinatal outcomes did not vary by region.

FUNDING

National Institute for Health and Care Research, Wellbeing of Women.

External validation of prognostic models to predict stillbirth using International Prediction of Pregnancy Complications (IPPIC) Network database: individual participant data meta-analysis

OBJECTIVE

Stillbirth is a potentially preventable complication of pregnancy. Identifying women at high risk of stillbirth can guide decisions on the need for closer surveillance and timing of delivery in order to prevent fetal death. Prognostic models have been developed to predict the risk of stillbirth, but none has yet been validated externally. In this study, we externally validated published prediction models for stillbirth using individual participant data (IPD) meta-analysis to assess their predictive performance.

METHODS

MEDLINE, EMBASE, DH-DATA and AMED databases were searched from inception to December 2020 to identify studies reporting stillbirth prediction models. Studies that developed or updated prediction models for stillbirth for use at any time during pregnancy were included. IPD from cohorts within the International Prediction of Pregnancy Complications (IPPIC) Network were used to validate externally the identified prediction models whose individual variables were available in the IPD. The risk of bias of the models and cohorts was assessed using the Prediction study Risk Of Bias ASsessment Tool (PROBAST). The discriminative performance of the models was evaluated using the C-statistic, and calibration was assessed using calibration plots, calibration slope and calibration-in-the-large. Performance measures were estimated separately in each cohort, as well as summarized across cohorts using random-effects meta-analysis. Clinical utility was assessed using net benefit.

RESULTS

Seventeen studies reporting the development of 40 prognostic models for stillbirth were identified. None of the models had been previously validated externally, and the full model equation was reported for only one-fifth (20%, 8/40) of the models. External validation was possible for three of these models, using IPD from 19 cohorts (491 201 pregnant women) within the IPPIC Network database. Based on evaluation of the model development studies, all three models had an overall high risk of bias, according to PROBAST. In the IPD meta-analysis, the models had summary C-statistics ranging from 0.53 to 0.65 and summary calibration slopes ranging from 0.40 to 0.88, with risk predictions that were generally too extreme compared with the observed risks. The models had little to no clinical utility, as assessed by net benefit. However, there remained uncertainty in the performance of some models due to small available sample sizes.

CONCLUSIONS

The three validated stillbirth prediction models showed generally poor and uncertain predictive performance in new data, with limited evidence to support their clinical application. The findings suggest methodological shortcomings in their development, including overfitting. Further research is needed to further validate these and other models, identify stronger prognostic factors and develop more robust prediction models. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Annual body mass index gain and risk of hypertensive disorders of pregnancy in a subsequent pregnancy

Weight gain during interpregnancy period is related to hypertensive disorders of pregnancy (HDP). However, in interpregnancy care/counseling, the unpredictability of the timing of the next conception and the difficulties in preventing age-related body weight gain must be considered while setting weight management goals. Therefore, we suggest considering the annual change in the body mass index (BMI). This study aimed to clarify the association between annual BMI changes during the interpregnancy period and HDP risk in subsequent pregnancies. A multicenter retrospective study of data from 2009 to 2019 examined the adjusted odds ratio (aOR) of HDP in subsequent pregnancies. The aORs in several annual BMI change categories were also calculated in the subgroups classified by HDP occurrence in the index pregnancy. This study included 1,746 pregnant women. A history of HDP (aOR, 16.76; 95% confidence interval [CI], 9.62 - 29.22), and annual BMI gain (aOR, 2.30; 95% CI, 1.76 - 3.01) were independent risk factors for HDP in subsequent pregnancies. An annual BMI increase of ≥ 1.0 kg/m2/year was related to HDP development in subsequent pregnancies for women without a history of HDP. This study provides data as a basis for interpregnancy care/counseling, but further research is necessary to validate our findings and confirm this relationship.

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.

Analysis of Proteinuria Estimation Methods in Hypertensive Disorders of Pregnancy

Purpose of the Study

The gold-standard 24-h urine collection method for protein estimation is inconvenient and is associated with a delay in laboratory analysis. This study was undertaken to compare sulphosalicylic acid test, urine dipstick test, urine protein-to-creatinine ratio with 24-h urine protein estimation in pre-eclampsia cases.

Methods

This is a comparative study and consists of a single group of 764 subjects. This study was conducted in the Department of Obstetrics and Gynaecology in collaboration with the Department of Biochemistry, JIPMER, Pondicherry, India, from February 2011 to January 2014. The subjects included were 764 pre-eclampsia women. A first voided morning sample was obtained for sulphosalicylic acid test, dipstick test, urine protein and creatinine estimation and urine culture, and subsequent urine samples were collected for the 24-h urine protein estimation.

Main Findings

For significant proteinuria, sulphosalicylic acid test with 1 + proteinuria has sensitivity, specificity, PPV and NPV of 59, 48, 39, 67, whereas with 2 + has sensitivity, specificity,PPV and NPV of 44, 88, 75 and 67%, respectively, dipstick test with 1 + proteinuria has sensitivity, specificity, PPV and NPV of 71, 52, 54 and 70%, whereas with 2 + has sensitivity, specificity,PPV and NPV of 49, 87, 75 and 69%, respectively. The spot urine protein-to-creatinine ratio and 24-h urine protein were significantly correlated (r = 0.98; p < 0.0001). The cut-off value for the protein-to-creatinine ratio as an indicator of protein excretion ≥ 300 mg/day was 0.285. The sensitivity, specificity PPV and NPV were 100, 99, 100 and 99%, respectively.

Conclusion

The spot urine protein-to-creatinine ratio is a better method for estimation of proteinuria in pre-eclampsia.

Recurrence of pre-eclampsia and the risk of future hypertension and cardiovascular disease: a systematic review and meta-analysis

Background

Women with a history of hypertensive disorders, including pre‐eclampsia, during pregnancy have a two‐ to‐five‐fold increased risk of cardiovascular disease (CVD). In 15% of women, pre‐eclampsia recurs in the following pregnancy.

Objectives

To evaluate all evidence on the future risk of developing hypertension and CVD after multiple pregnancies complicated by pre‐eclampsia compared with pre‐eclampsia in a single pregnancy followed by normal subsequent pregnancy.

Search strategy

Embase and Medline were searched until June 2017.

Selection criteria

All relevant studies on the risk of developing hypertension, atherosclerosis, ischaemic heart disease, cerebrovascular accident (CVA), thromboembolism, heart failure or overall hospitalisation and mortality due to CVD after having had recurrent pre‐eclampsia.

Data collection and analysis

Twenty‐two studies were included in the review. When possible, we calculated pooled risk ratios (RR) with 95% CI through random‐effect analysis.

Main results

Recurrent pre‐eclampsia was consistently associated with an increased pooled risk ratio of hypertension (RR 2.3; 95% CI 1.9–2.9), ischaemic heart disease (RR 2.4; 95% CI 2.2–2.7), heart failure (RR 2.9; 95% CI 2.3–3.7), CVA (RR 1.7; 95% CI 1.2–2.6) and hospitalisation due to CVD (RR 1.6; 95% CI 1.3–1.9) when compared with women with subsequent uncomplicated pregnancies. Other studies on thromboembolism, atherosclerosis and cardiovascular mortality found a positive effect, but data could not be pooled.

Conclusions

This systematic review and meta‐analysis support consistent higher risk for future development of hypertension and CVD in women with recurring pre‐eclampsia as opposed to women with a single episode of pre‐eclampsia.

Tweetable abstract

The risk of future cardiovascular disease increases when women have recurrence of pre‐eclampsia compared with a single episode.

The risk of future cardiovascular disease increases when women have recurrence of pre‐eclampsia compared to a single episode.

This paper includes Author Insights, a video abstract available at https://vimeo.com/rcog/authorinsights15394

The role of placental histopathological lesions in predicting recurrence of preeclampsia

OBJECTIVE

We aimed to study the role of placental pathology in the prediction of preeclampsia (PE) recurrence.

METHODS

The medical records and pathological placental reports of all women diagnosed with PE, during 2008-2015, were reviewed. The study population was divided according to the outcome of their subsequent pregnancy: those who did (recurrence group) or did not (no-recurrence group) develop recurrent PE. Data regarding maternal characteristics and placental maternal/fetal vascular malperfusion lesions, of the initial pregnancies, were compared. Two prediction models were generated for PE recurrence.

RESULTS

Compared to the no-recurrence group (n = 130), the recurrence group (n = 96) was characterized by lower gestational age (p < 0.001), longer inter-pregnancy interval (p = 0.012), and higher rate of severe features (p < 0.001). By logistic regression analysis composite maternal (aOR = 3.05, 95%CI 1.39-6.71, p = 0.005), fetal (aOR = 9.31, 95%CI 3.9-22.1, p < 0.001), and concurrent maternal + fetal (aOR = 13.94, 95%CI 5.08-38.21, p < 0.001), vascular malperfusion lesions were found to be independently associated with recurrence. A clinical prediction model accounted for 20.8% of PE recurrence (R²  = 0.208, AUC = 0.732), while a clinical-pathological model accounted for 34.2% of recurrence (R²  = 0.342, AUC = 0.80).

CONCLUSION

Placental maternal and fetal vascular malperfusion lesions are independently associated with increased risk for PE recurrence. A clinical-pathological prediction model for recurrence of PE is superior to a prediction model based merely on clinical factors. © 2016 John Wiley & Sons, Ltd.

Recurrence of hypertensive disorders of pregnancy: an individual patient data metaanalysis

OBJECTIVE

We performed an individual participant data (IPD) metaanalysis to calculate the recurrence risk of hypertensive disorders of pregnancy (HDP) and recurrence of individual hypertensive syndromes.

STUDY DESIGN

We performed an electronic literature search for cohort studies that reported on women experiencing HDP and who had a subsequent pregnancy. The principal investigators were contacted and informed of our study; we requested their original study data. The data were merged to form one combined database. The results will be presented as percentages with 95% confidence interval (CI) and odds ratios with 95% CI.

RESULTS

Of 94 eligible cohort studies, we obtained IPD of 22 studies, including a total of 99,415 women. Pooled data of 64 studies that used published data (IPD where available) showed a recurrence rate of 18.1% (n=152,213; 95% CI, 17.9-18.3%). In the 22 studies that are included in our IPD, the recurrence rate of a HDP was 20.7% (95% CI, 20.4-20.9%). Recurrence manifested as preeclampsia in 13.8% of the studies (95% CI,13.6-14.1%), gestational hypertension in 8.6% of the studies (95% CI, 8.4-8.8%) and hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome in 0.2% of the studies (95% CI, 0.16-0.25%). The delivery of a small-for-gestational-age child accompanied the recurrent HDP in 3.4% of the studies (95% CI, 3.2-3.6%). Concomitant HELLP syndrome or delivery of a small-for-gestational-age child increased the risk of recurrence of HDP. Recurrence increased with decreasing gestational age at delivery in the index pregnancy. If the HDP recurred, in general it was milder, regarding maximum diastolic blood pressure, proteinuria, the use of oral antihypertensive and anticonvulsive medication, the delivery of a small-for-gestational-age child, premature delivery, and perinatal death. Normotensive women experienced chronic hypertension after pregnancy more often after experiencing recurrence (odds ratio, 3.7; 95% CI, 2.3-6.1).

CONCLUSION

Among women that experience hypertension in pregnancy, the recurrence rate in a next pregnancy is relatively low, and the course of disease is milder for most women with recurrent disease. These reassuring data should be used for shared decision-making in women who consider a new pregnancy after a pregnancy that was complicated by hypertension.

Prediction of recurrence of hypertensive disorders of pregnancy in the term period, a retrospective cohort study

OBJECTIVES

To assess the recurrence risk of term hypertensive disease of pregnancy and to determine which potential risk factors are predictive of recurrence.

STUDY DESIGN

We performed a retrospective cohort study in two secondary and one tertiary care hospitals in the Netherlands. We identified women with a hypertensive disorder in the index pregnancy and delivery after 37weeks of gestation between January 2000 and December 2002. Data were extracted from medical files and women were approached for additional information on subsequent pregnancies. Adverse outcome was defined as recurrence of a hypertensive disorder in the next subsequent pregnancy.

MAIN OUTCOME MEASURES

The absolute risk of recurrence and a prediction model containing demographic and clinical factors predictive of recurrence.

RESULTS

We identified 638 women for potential inclusion, of whom 503 could be contacted. Of these women, 312 (62%) had a subsequent pregnancy. Hypertensive disorders recurred in 120 (38%, 95% CI 33-44) women, of whom 15 (5%, 95% CI 3-7) delivered preterm. Women undergoing recurrence were more at risk to develop chronic hypertension after pregnancy (35% versus 16%, OR 2.8, 95% CI 1.5-5.3). Body mass index, non-White European origin, chronic hypertension, maximum diastolic blood pressure, no use of anticonvulsive medication and interpregnancy interval were predictors for recurrence.

CONCLUSIONS

Women with hypertensive disorders and term delivery have a substantial chance of recurrence, but a small risk of preterm delivery. A number of predictors for recurrence could be identified and women with a recurrence more often developed chronic hypertension.