Planned early-term birth reduces preeclampsia risk

Preeclampsia incidence is reduced by planned early-term birth based on risk stratification for preeclampsia, according to a recent study published in The Lancet.¹

Preeclampsia impacts approximately 3% of pregnancies, with approximately 75% of cases occurring at term for gestational age.² The Fetal Medicine Foundation (FMF) competing-risks model may be used at 11- to 13-weeks’ gestation to determine risk, but this method does not influence term preeclampsia risk.¹

“Evidence shows that planned delivery at term might be an intervention that can reduce the incidence of pre-eclampsia at term,” wrote investigators.

Randomization and risk assessment strategy

The open-label, randomized trial was conducted to evaluate the impact of offering risk stratified, planned, early-term birth after screening toward subsequent preeclampsia. Participants were recruited from King’s College Hospital National Health Service (NHS) Foundation Trust and Medway NHS Foundation Trust.

Recruitment was performed during patients’ visits to a routine ultrasound scan at 35- to 36-weeks’ gestation. Women with a singleton pregnancy resulting in a live fetus without major anomalies were eligible for inclusion. Exclusion criteria included being aged under 16 years, having preeclampsia, and participating in a conflicting trial.

A central computerized service was used to randomize patients 1:1 to an intervention or usual care group. Those in the intervention group underwent preeclampsia risk assessment using the FMF competing-risks model. This model combines maternal factors with biomarkers to provide individualized preeclampsia risk assessment.

Risk-stratified early-term birth intervention

The model assumed preeclampsia would present in all women if the pregnancy were to continue indefinitely. Model fit and interpretability were considered when selecting a Gaussian model for gestational age at birth. Risk-stratified planned early term birth was offered to patients with a preeclampsia risk of at least 1 in 50.

This could be performed at 37-, 38-, 39-, or 40-weeks’ gestation. The procedure was offered earlier to patients with an increased risk. In comparison, management was performed based on local hospital procedures among patients with a risk score below 1 in 50.

In the control group, the timing of birth was determined by spontaneous onset of labor, clinical indications, or maternal request. Birth with preeclampsia was reported as the primary outcome, determined based on the 2021 definition from the International Society for the Study of Hypertension in Pregnancy.

Emergency cesarean section and neonatal care unit stay of at least 48 consecutive hours were reported as secondary outcomes. Investigators also monitored adherence and severe adverse events.

Reduced preeclampsia rates

There were 8136 women randomized to either the intervention or usual care group. These patients were often in their early 30s and overweight, with 74.1% self-identifying as White. Only 2.7% were smokers, 3.7% had a family history of preeclampsia, and 2.2% had medical comorbidities.

Balanced baseline characteristics were reported between the intervention and usual care groups. Rates of birth with preeclampsia were 3.9% among the intervention group vs 5.6% of the usual care group, with an adjusted risk ratio (RR) of 0.70 in the intervention group. Consistent treatment effects were observed across patient subgroups.

Secondary outcomes did not significantly differ between groups. This included emergency cesarean section with a rate of 22.8% in the intervention group vs 21.6% in the control group and neonatal care unit admission with a rate of 6.5% in the intervention group vs 6.8% in the control group. Adjusted RRs for these outcomes in the intervention group were 1.06 and 0.96, respectively.

Safety findings and implications

More women presented with gestational hypertension in the intervention group vs the control group, though a numerically greater decline in preeclampsia was also reported. No significant between-group differences in the incidence of severe adverse events were reported, at 0.2% in the intervention group and 0.1% in the control group.

Overall, the results indicated a 30% reduction in post-screening preeclampsia from the intervention. Additionally, no increase in cesarean birth or neonatal morbidity was reported.

“To our knowledge, this is the first trial to show that a personalized approach to near-term pre-eclampsia risk assessment can reduce the incidence of disease in the maternity population,” wrote investigators.

References

1. Goadsby J, Syngelaki A, Magee LA, et al. Scheduled birth at term for the prevention of pre-eclampsia (PREVENT-PE): an open-label randomised controlled trial. The Lancet. 2025;407. doi:10.1016/S0140-6736(25)01207-3
2. von Dadelszen P, Syngelaki A, Akolekar R, et al. Preterm and term pre-eclampsia: relative burdens of maternal and perinatal complications. BJOG. 2023;130:524-530.