Efficacy of Progesterone Therapy in the Prevention of Preterm Labor in Women with Mixed Risk-factors: A Systematic Review and Meta-analysis of Randomized Clinical Trials

Background: Preterm birth is a worldwide concern with widespread negative consequences. Therefore, prevention of preterm birth has become a top priority of health managers and clinicians in recent decades.Objective: To evaluate the efficacy of progesterone therapy in the prevention of preterm labor in women with mixed risk factors.Search strategy: An extensive search of electronic databases was done (date last searched April 2016). No restrictions of language, time, or geographic location were applied.Inclusion criteria: All randomized clinical trials of singleton pregnancies with multiple risk factors (including prior preterm birth and short cervical length) that were randomized to treatment with progesterone (intervention group) and placebo or no treatment (control group) were included in meta-analysis.Primary outcome: Our primary outcome was gestational age at delivery.Results: Three Randomized Clinical Trials (521 subjects and 37,823 control women) were included. A random effect model showed that mean gestational age at delivery of progesterone group is 0.18 (-0.41–0.77) month longer than that of control group with with 95% confidence interval but this difference is not statically significant.Conclusions: Progesterone therapy does not have sufficient efficacy in the prevention of preterm labor in women with multiple risk factors. However, further investigation is required to unequivocally establish this result.