Progesterone for the prevention of preterm birth: A critical evaluation of evidence

Abstract A systematic review of the literature identified nine randomised trials that evaluated the effects of progestational agents in the prevention of preterm delivery. These studies were of variable quality. Meta-analyses showed reductions in delivery rates before 37 weeks (OR 0.42, 95% CI 0.31–0.57) and 34 weeks (OR 0.51, 95% CI 0.34–0.77) as well as in respiratory distress syndrome (OR 0.55, 95% CI 0.31–0.96) with progestational agents. A cumulative meta-analysis showed that the treatment benefit for the outcome of delivery before 37 weeks exceeded the conventional level of statistical significance in 1975 ( p p -value was p