Do Progesterone Injections Prevent Recurrent Preterm Birth?

Results from some studies have suggested that 17 α-hydroxyprogesterone caproate (17P) reduces the incidence of preterm delivery. In this study, funded by the National Institute of Child Health and Human Development, women at 19 U.S. clinical centers were randomized to receive weekly injections of 17P (n=310) or placebo (castor oil; n=153), beginning at 16-20 weeks' gestation and continuing until 36 weeks' gestation or delivery. All participants had histories of spontaneous preterm labor in a previous pregnancy.

17P injections significantly reduced the rate of preterm delivery at less than 37 weeks' gestation (36.3% vs. 54.9% with placebo). Similar risk reductions were noted for deliveries at less than 35 or 32 weeks' gestation. Necrotizing e…