Prevention of preterm delivery after successful tocolysis in preterm labor by 17 alpha-hydroxyprogesterone caproate: A randomized controlled trial

OBJECTIVE: The objective of the study was to evaluate the use of 17 alpha-hydroxyprogesterone caproate (17P) to reduce preterm delivery. STUDY DESIGN: This open-label, multicenter, randomized controlled trial included women with singleton pregnancies admitted at 24-31 weeks' gestation and cervical length less than 25 mm for preterm labor successfully arrested by tocolytic treatment. Randomization assigned them to receive (or not) 500 mg of intramuscular 17P after tocolysis ended, repeated semiweekly until 36 weeks or preterm delivery. The primary outcome was the time from randomization to delivery. RESULTS: Outcome data were available for 184 of 188 women randomized. The 17P and control groups (similar for most baseline characteristics) did not differ significantly for median [interquartile range] time to delivery (64 [42-79] and 67 [46-83] days, respectively) or rates of delivery before 37, 34, or 32 weeks of gestation or adverse perinatal outcomes. CONCLUSION: Semiweekly injections of 17P did not prolong pregnancy significantly in women with tocolysis-arrested preterm labor.