OC01.01: Prevention of preterm delivery in twin gestations (PREDICT): a multicentre randomised placebo‐controlled trial on the effect of vaginal micronised progesterone

Abstract

Progesterone treatment in second and third trimester of pregnancy has been shown to reduce the risk of preterm delivery in high-risk singleton gestations. This study was conducted to investigate the preventive effect of vaginal progesterone in a large population of twin gestations. A double-blind, placebo-controlled randomised trial was performed in 17 centres in Denmark and Austria. Women with twin gestations were randomised at 20–24 weeks' gestation to daily treatment with progesterone pessaries or identically looking placebo pessaries until 34 weeks' gestation. Primary outcome was spontaneous delivery or intrauterine death before 34 weeks' gestation. Secondary outcomes were neonatal complications and long-term infant follow-up by Ages and Stages Questionnaire (ASQ) at 6 and 18 months of age. All analyses were performed according to the intention-to-treat principle. A total of 677 women were randomised (334 to the progesterone group and 343 to the placebo group). Two women in the placebo group were lost to follow-up. Baseline characteristics for the progesterone and placebo group were similar. The rate of spontaneous delivery or intrauterine death before 34 weeks was 12.6% in the progesterone group versus 15.5% in the placebo group, odds ratio 0.8 (95% confidence interval 0.5–1.2). Risks of selected maternal and neonatal complications were comparable for the groups. Mean ASQ-score at 6 months was 215 for infants in the progesterone group and 218 for infants in the placebo group (P = 0.45), and 193 and 194, respectively, at 18 months of age (P = 0.89). Progesterone treatment did not prevent preterm delivery in twin gestations. No beneficial or harmful effects were observed in women or infants.