Planned delivery or expectant management in preeclampsia: an individual participant data meta-analysis.

OBJECTIVE: Pregnancy hypertension is a leading cause of maternal and perinatal mortality and morbidity. Between 34+0 and 36+6 weeks gestation, it is uncertain whether planned delivery could reduce maternal complications without serious neonatal consequences. In this individual participant data meta-analysis, we aimed to compare planned delivery to expectant management, focusing specifically on women with preeclampsia. DATA SOURCES: We performed an electronic database search using a prespecified search strategy, including trials published between January 1, 2000 and December 18, 2021. We sought individual participant-level data from all eligible trials. STUDY ELIGIBILITY CRITERIA: We included women with singleton or multifetal pregnancies with preeclampsia from 34 weeks gestation onward. METHODS: The primary maternal outcome was a composite of maternal mortality or morbidity. The primary perinatal outcome was a composite of perinatal mortality or morbidity. We analyzed all the available data for each prespecified outcome on an intention-to-treat basis. For primary individual patient data analyses, we used a 1-stage fixed effects model. RESULTS: We included 1790 participants from 6 trials in our analysis. Planned delivery from 34 weeks gestation onward significantly reduced the risk of maternal morbidity (2.6% vs 4.4%; adjusted risk ratio, 0.59; 95% confidence interval, 0.36-0.98) compared with expectant management. The primary composite perinatal outcome was increased by planned delivery (20.9% vs 17.1%; adjusted risk ratio, 1.22; 95% confidence interval, 1.01-1.47), driven by short-term neonatal respiratory morbidity. However, infants in the expectant management group were more likely to be born small for gestational age (7.8% vs 10.6%; risk ratio, 0.74; 95% confidence interval, 0.55-0.99). CONCLUSION: Planned early delivery in women with late preterm preeclampsia provides clear maternal benefits and may reduce the risk of the infant being born small for gestational age, with a possible increase in short-term neonatal respiratory morbidity. The potential benefits and risks of prolonging a pregnancy complicated by preeclampsia should be discussed with women as part of a shared decision-making process.

Early and late onset pre-eclampsia and small for gestational age risk in subsequent pregnancies.

BACKGROUND: Pre-eclampsia shares pathophysiology with intrauterine growth restriction. OBJECTIVE: To investigate whether delivery of a small for gestational age (SGA) infant in the 1st pregnancy increases the risk of early and late onset pre-eclampsia in the 2nd pregnancy. Conversely, we investigated whether pre-eclampsia in the 1st pregnancy impacts SGA risk in the 2nd pregnancy. STUDY DESIGN: We studied a cohort from the Dutch Perinatal Registry of 265,031 women with 1st and 2nd singleton pregnancies who delivered between 2000 and 2007. We analyzed 2nd pregnancy risks of early and late onset pre-eclampsia-defined by delivery before or after 34 gestational weeks-as well as SGA below the 5th and between the 5th and 10th percentiles risks with multivariable logistic regressions. Interaction terms between 1st pregnancy hypertension, pre-eclampsia, SGA, and delivery before or after 34 gestational weeks were included in the regressions. RESULTS: First pregnancy early onset pre-eclampsia increased risk of SGA <5th percentile (OR 2.1, 95% CI 1.7-2.7) in the 2nd pregnancy. Late onset pre-eclampsia increased the SGA <5th percentile marginally (OR 1.1, 95% CI 1.0-1.3). In the absence of 1st pregnancy hypertensive disorder, women who delivered an SGA infant in their 1st pregnancy were at increased risk of 2nd pregnancy late onset pre-eclampsia (SGA <5th: OR 2.05, 95% CI 1.58-2.66; SGA 5-10th: OR 1.39, 95% CI 1.01-1.93). Early onset 2nd pregnancy pre-eclampsia risk was also increased, but this was only statistically significant for women who delivered an SGA infant below the 5th percentile in the 1st pregnancy (SGA <5th: OR 2.44, 95% CI 1.19-5.00; SGA 5-10th: OR 1.69, 95% CI 0.68-4.24;). CONCLUSION: Women with 1st pregnancy early onset pre-eclampsia have increased risk of SGA <5th percentile in the 2nd pregnancy. SGA in the 1st pregnancy increases pre-eclampsia risk in the 2nd pregnancy even in the absence of hypertensive disorders in the 1st pregnancy, although absolute risks remain low. These findings strengthen the evidence base associating intrauterine growth restriction with early onset pre-eclampsia.

Recurrence risk of preeclampsia in a linked population-based cohort: Effects of first pregnancy maximum diastolic blood pressure and gestational age.

OBJECTIVE: To estimate preeclampsia occurrence and recurrence risk in the 2nd pregnancy and analyze associated risk factors such as 1st pregnancy maximum diastolic blood pressure (maxDBP) and gestational age at delivery (GA). STUDY DESIGN: Linked cohort of 1st and 2nd pregnancies of 272,551 women from the Dutch Perinatal Registry collected between 2000 and 2007. We defined preeclampsia as hypertension (maxDBP ≥90 mmHg or documented hypertension) plus proteinuria (≥300 mg/24 h) and analyzed its 2nd pregnancy occurrence with logistic regression. Early and late onset preeclampsia were defined by delivery before and after the 34th week, respectively. RESULTS: Preeclampsia prevalences in the 1st and 2nd pregnancies were 2.5% and 0.9%, respectively. Women with prior preeclampsia had a 10.5% risk of recurrence. For women with term 1st pregnancies and maxDBP <80 mmHg, the 2nd pregnancy preeclampsia rate was 0.2% (95% CI 0.17%-0.23%), while for those whom presented maxDBP ≥110 mmHg it was 4.2% (95% CI 3.6%-4.8%). First pregnancy late onset preeclampsia was associated with increased preeclampsia recurrence risk proportional to 1st pregnancy maxDBP: in women with a maxDBP between 100 and 109 mmHg the recurrence risk was 8.3%, while for women with a maxDBP ≥110 mmHg this risk was 11% (difference 2.7%; 95% CI 1.0%-4.4%). In 1st pregnancy early onset preeclampsia corresponding rates were 14.8% and 19.3% (difference 4.5%; 95% CI -1.3%-9.7%). CONCLUSION: Preeclampsia recurrence risk is 10%. Preeclampsia risk in the 2nd pregnancy increases proportionally to 1st pregnancy maxDBP. Earlier onsets of 1st pregnancy preeclampsia further increase recurrence risk.

Relevance of individual participant data meta-analysis for studies in obstetrics: delivery versus expectant monitoring for hypertensive disorders of pregnancy.

Like many other research subjects in obstetrics, research on immediate delivery versus expectant monitoring for women with hypertensive disorders of pregnancy faces certain challenges when it comes to interpretation and generalisation of the results; relatively rare outcomes are studied, in a clinically heterogeneous population, while the clinical practice in some countries has dictated that studies in term pregnancy were completed before earlier gestational ages could be studied. This has resulted in multiple smaller studies, some studying surrogate outcome measures, with different in- and exclusion criteria, and without enough power for reliable subgroup analyses. All this complicates the generation of definitive answers and implementation of the results into clinical practice. Performing multiple studies and subsequently pooling their results in a meta-analysis can be a way to overcome the difficulties of studying relatively rare outcomes and subgroups with enough power, as well as a solution to reach a final answer on questions involving an uncertain and possibly harmful intervention. However, in the case of the current studies on delivery versus expectant monitoring in women with hypertensive disorders of pregnancy, differences regarding eligibility criteria, outcome measures and subgroup definitions make it difficult to pool their results in an aggregate meta-analysis. Individual patient data meta-analysis (IPDMA) has the potential to overcome these challenges, because it allows for flexibility regarding the choice of endpoints and standardisation of inclusion and exclusion criteria across studies. In addition, it has more statistical power for informative subgroup analyses. We therefore propose an IPDMA on immediate delivery versus expectant monitoring for hypertensive disorders of pregnancy, and advocate the use of IPDMA for research questions in obstetrics that face similar challenges.