Multicenter Randomized Trial of an sFlt-1/PlGF Ratio-Based Algorithm for Timing of Delivery in Early-Onset Severe Preeclampsia: The MAP 2 Study

Preeclampsia is a serious pregnancy complication caused by abnormal placental development and function. It can lead to high blood pressure and damage to organs such as the liver, kidneys, brain, or cardiovascular system. In these cases, the only definitive treatment is delivery. However, deciding when to deliver is challenging: delaying delivery increases risks for both mother and baby, while delivering too early increases complications related to prematurity.

This study aims to evaluate whether a blood test measuring the sFlt-1/PlGF ratio an angiogenic marker that reflects placental function and predicts complications more accurately than traditional clinical criteria can help determine the optimal timing of delivery in women with severe preeclampsia between 30 weeks and 33 weeks plus 6 days of gestation. It is a multicenter, randomized controlled clinical trial conducted in 11 referral hospitals in Spain and will include 386 singleton pregnancies.

Participants will be randomly assigned to one of two groups. In the control group, standard expectant management will be followed, aiming to continue the pregnancy until 34 weeks if maternal and fetal conditions remain stable, and the sFlt-1/PlGF results will be masked. In the study group, delivery timing will be guided by the sFlt-1/PlGF ratio: if the ratio is greater than 655, delivery will be planned from 30 weeks onward; if greater than 110, delivery will be planned from 34 weeks; and if 110 or lower, pregnancy may continue until 37 weeks.

The study has two primary outcomes. The first is a composite of severe maternal complications, including neurological, hepatic, renal, respiratory, or cardiovascular dysfunction, severe hypertension, placental abruption, or fetal death. The second is a composite of neonatal complications, including admission to the neonatal intensive care unit or neonatal death.

The goal is to demonstrate that using angiogenic markers reduces maternal complications without significantly increasing neonatal complications. If successful, this approach could support more individualized management of early-onset severe preeclampsia, improving maternal safety while carefully balancing the risks of prematurity for the newborn.