Objective Preterm rupture of membranes (PROM) is associated with an increased risk of preterm birth and neonatal morbidity. Prophylactic 17-hydroxyprogesterone caproate (17OHP-C) reduces the risk of preterm birth in some women who are at risk for preterm birth. We sought to test whether 17OHP-C would prolong pregnancy or improve perinatal outcome when given to mothers with preterm rupture of the membranes. Study Design This is a multicenter, double-blind, placebo-controlled, randomized clinical trial. The study included singleton pregnancies with gestational ages from 23 0/7 to 30 6/7 weeks at enrollment, documented PROM, and no contraindication to expectant management. Consenting women were assigned randomly to receive weekly intramuscular injections of 17OHP-C (250 mg) or placebo. The primary outcome was continuation of pregnancy until a favorable gestational age, which was defined as either 34 0/7 weeks of gestation or documentation of fetal lung maturity at 32 0/7 to 33 6/7 weeks of gestation. The 2 prespecified secondary outcomes were interval from randomization to delivery and composite adverse perinatal outcome. The planned sample size was 222 total women. Results From October 2011 to April 2014, 152 women were enrolled; 74 women were allocated randomly to 17OHP-C, and 78 were allocated randomly to placebo. The trial was stopped when results of a planned interim analysis suggested that continuation was futile. The primary outcome was achieved in 3% of the 17OHP-C group and 8% of the placebo group ( P = .18). There was no significant between-group difference in the prespecified secondary outcomes, randomization-to-delivery interval (17.1 ± 16.1 vs 17.0 ± 15.8 days, respectively; P = .76) or composite adverse perinatal outcome (63% vs 61%, respectively; P = .93). No significant differences were found in other outcomes, which included rates of chorioamnionitis, postpartum endometritis, cesarean delivery, individual components of the composite outcome, or prolonged neonatal length of stay. Conclusion Compared with placebo, weekly 17OHP-C injections did not prolong pregnancy or reduce perinatal morbidity in patients with PROM in this trial.
