Planned delivery for late preterm preeclampsia reduces maternal morbidity

Reference

Chappell LC, Brocklehurst P, Green ME, at al, for the Phoenix Study Group. Planned early delivery or expectant management for late preterm pre-eclampsia (PHOENIX): a randomised controlled trial. Lancet 2019;394(10204):1181-1190.

Synopsis

This was a complex multicenter study of women with preeclampsia or chronic hypertension with superimposed pre-eclampsia conducted in 46 maternity units in the United Kingdom. The authors included 901 women who were at least 18 years old and had a singleton or dichorionic twin pregnancy with at least one viable fetus. The main exclusion criterion was a decision to deliver made prior to randomization. The study was stratified to balance for study center, twin gestation, severity of hypertension, parity, previous cesarean delivery, and gestational age at randomization. Enrollment took place at between 34 0/7 and 36 6/7 weeks' gestation. Planned delivery consisted of initiation of delivery within 48 hours after randomization, a period expected as necessary in some cases to allow time to administer corticosteroids to stimulate fetal lung maturation and assure neonatal bed availability. The control group had expectant management, allowing the pregnancy to continue until 37 completed weeks unless there was a medical indication for delivery, which occurred in 54%. Length of gestation was a median 252 days in the planned delivery group versus 257 in the expectant management group. The principle maternal outcome was a composite including progression to severe preeclampsia and a long list of possible morbidities related to the central nervous system; cardiorespiratory, hematological, hepatic, and renal systems; and placental abruption. The maternal composite outcome results favored planned delivery (65% vs 75%; adjusted relative risk [aRR] 0.86; 95% CI 0.79 - 0.94; P = .0005). Multiple elements of the composite also favored planned delivery, including progression to severe preeclampsia and the likelihood of a vaginal delivery (36% vs 29%; aRR 1.21; 1.04 - 1.41). The perinatal outcome was a composite of perinatal deaths or neonatal intensive care admission, which did not favor planned delivery (42% vs 34%; aRR 1.26; 1.08 - 1.46; P = .0034). There were no neonatal deaths. On further analysis the authors determined that the indication for neonatal unit admissions was based on prematurity and that there were no significant differences between groups for multiple secondary outcomes, including the need for respiratory support or newborn length of hospital stay.