Vaginal Progesterone to Prevent Preterm Delivery in Unselected Women with Twin Pregnancy: a Randomised, Placebo-controlled, Double-blind Trial

Abstract

Objective: To evaluate the efficacy of vaginal progesterone in preventing preterm birth before 34 weeks in unselected twin pregnancies.
Methods: Women with a twin pregnancy were randomised in a one-to-one ratio to receive either 100 mg daily vaginal progesterone or placebo from 24 to 34 weeks of gestation. Low vaginal swab, serum human chorionic gonadotrophin, progesterone, C-reactive protein, and 75 g oral glucose tolerance test were examined at recruitment and at 30 to 32 weeks of gestation. The primary outcome was the rate of preterm delivery before 34 weeks.
Results: Of 165 women recruited, 23 were excluded and 142 were included for analysis, of whom 71 received vaginal progesterone and 71 received placebo. Basic demographics of the two groups were similar. The treatment and placebo groups were comparable in terms of maternal, obstetric, and neonatal outcomes, including the preterm delivery rate before 34 weeks (31% vs. 20%, p=0.123) and gestational age at delivery (35.3±2.6 weeks vs. 35.7±2.1 weeks, p=0.614).
Conclusion: In unselected women with twin pregnancy, vaginal progesterone did not prevent preterm delivery.