Scheduled birth at term for the prevention of pre-eclampsia (PREVENT-PE): an open-label randomised controlled trial

BACKGROUND: In high-risk pregnancies, there is no reliable intervention to reduce term pre-eclampsia. We aimed to investigate the effect of screening for pre-eclampsia risk at 36 weeks' gestation and offering risk-stratified, planned, early-term birth. METHODS: PREVENT-PE was an open-label, adaptive (planned, for sample size), randomised controlled trial, done at two maternity hospitals in the UK. We included women (aged ≥16 years) with a singleton pregnancy, live fetus without major anomalies, and ability to provide informed consent, without pre-eclampsia or participation in conflicting trials. Consenting women were randomly assigned (by a central computerised service, 1:1, in random permuted blocks of variable size, stratified by site) to the intervention group (pre-eclampsia risk assessment and, for women with a pre-eclampsia risk ≥1 in 50, risk-stratified planned early-term birth) or control group (usual care at term). The primary outcome was birth with pre-eclampsia (International Society for the Study of Hypertension in Pregnancy criteria). This trial is registered with ISRCTN, ISRCTN41632964. FINDINGS: weeks' gestation between May 9, 2023, and June 7, 2024, 10 803 (95·8%) were eligible. Of 8136 women (75·3%) randomly assigned, six (0·1%) withdrew consent and 36 (0·4%) were randomly assigned in error, leaving 8094 (99·5%) in the final analyses: 4037 (49·9%) women in the intervention group and 4057 (50·1%) in the control group. 2098 (25·9%) of 8094 women self-reported non-White ethnicity and 5996 (74·1%) self-reported White ethnicity. Pre-eclampsia occurred in 158 (3·9%) of 4037 births in the intervention group and in 226 (5·6%) of 4057 in the control group (adjusted risk ratio 0·70 95% CI 0·58-0·86; intention-to-treat analysis with imputation). Serious adverse events did not differ between the intervention group (five 0·1% of 4031) and control group (ten 0·2% 4048; Fisher's exact test p=0·30). INTERPRETATION: Planned early-term birth based on risk stratification for pre-eclampsia reduced the incidence of pre-eclampsia, without increasing emergency caesarean section or neonatal care unit admission. FUNDING: Fetal Medicine Foundation.