17-hydroxyprogesterone caproate for twin pregnancy: a double-blind, randomized clinical trial

OBJECTIVE: We sought to determine whether prophylactic treatment with 17-alpha-hydroxyprogesterone caproate (17Pc) in twin pregnancy will reduce neonatal morbidity (primary outcome) by prolonging pregnancy (secondary outcome). STUDY DESIGN: This was a double-blind, randomized clinical trial. Mothers carrying dichorionic-diamniotic twins were randomly assigned (in a 2:1 ratio) to weekly injections of 250 mg of 17Pc or placebo, starting at 16-24 weeks and continued until 34 weeks. RESULTS: In all, 160 women were randomized to 17Pc and 80 to placebo. Composite neonatal morbidity occurred with similar frequency in the 17Pc and placebo groups (14% vs 12%, respectively, P = .62). Mean gestational age at delivery was not affected by 17Pc (35.3 vs 35.9 weeks, P = .10), but a 3-day difference in median gestational age favored placebo (P = .02). There were no perinatal deaths with 17Pc and 3 with placebo. CONCLUSION: In twin pregnancy, prophylactic treatment with 17Pc did not prolong gestation or reduce neonatal morbidity.