Scheduled Birth at Term Reduced Pre-Eclampsia in PREVENT-PE

Key Takeaways

• Birth with pre-eclampsia occurred in 3.9% of the intervention group and 5.6% of the usual-care group.
• The strategy used 36-week risk assessment and offered planned early-term birth when estimated pre-eclampsia risk was at least 1 in 50.
• Serious adverse events were similar between groups, with no reported increase in emergency caesarean section or neonatal care unit admission.

In the PREVENT-PE trial, risk-stratified planned early-term birth was associated with an adjusted risk ratio of 0.70 for pre-eclampsia versus usual care at term in an open-label, adaptive randomized trial at two UK maternity hospitals. The study enrolled women with singleton pregnancies and no pre-eclampsia who attended routine fetal ultrasound screening from 35+0 to 36+6 weeks and underwent formal pre-eclampsia risk assessment at 36 weeks' gestation. The intervention group had a lower observed incidence of pre-eclampsia than the usual-care group.

Eligible participants were women aged 16 years or older with a singleton pregnancy, a live fetus without major anomalies, capacity to provide informed consent, and no pre-eclampsia. Women participating in conflicting trials were excluded, and consenting women were assigned through a central computerized service in a 1:1 ratio. One group received risk assessment plus planned early-term birth when estimated individual pre-eclampsia risk reached at least 1 in 50. The comparator was usual care at term, and the primary endpoint was birth with pre-eclampsia using International Society for the Study of Hypertension in Pregnancy criteria. Of 11,280 women presenting for ultrasound, 10,803 were eligible, 8,136 were randomized, and 8,094 were included in the final analyses.

Among the women included in the analyses, 4,037 were in the intervention arm and 4,057 were in the control arm. Birth with pre-eclampsia occurred in 158 births in the intervention group and 226 in the control group, with a 95% confidence interval of 0.58 to 0.86 around the adjusted estimate in an intention-to-treat analysis with imputation. Among analyzed participants, 2,098 women, or 25.9%, self-reported non-White ethnicity, while 5,996, or 74.1%, self-reported White ethnicity. Overall, birth with pre-eclampsia was less frequent in the intervention group than in the control group.

Serious adverse events occurred in five of 4,031 women, or 0.1%, in the intervention group and ten of 4,048, or 0.2%, in the control group. There was no significant between-group difference, with Fisher's exact test yielding p=0.30. The authors interpreted the findings as showing reduced pre-eclampsia incidence without increased emergency caesarean section or neonatal care unit admission.