ObjectiveTo identify, appraise, and summarize the evidence from randomized controlled trials (RCTs) comparing oral dydrogesterone to vaginal progesterone capsules for luteal-phase support (LPS) in women offered fresh or frozen embryo transfers following in vitro fertilization.MethodsTwo independent authors screened the literature for papers based on titles and abstracts, then selected the studies, extracted data, and assessed the risk of bias. Dydrogesterone and progesterone were compared based on risk ratios (RR) and the precision of the estimates was assessed through the 95% confidence interval (CI).ResultsAn electronic search performed on June 7, 2017 retrieved 376 records, nine of which were papers deemed eligible and included in this systematic review and quantitative analysis. Good quality evidence indicates that oral dydrogesterone provided at least similar results than vaginal progesterone capsules on live birth/ongoing pregnancy (RR=1.08, 95%CI=0.92-1.26, I2=29%, 8 RCTs, 3,386 women) and clinical pregnancy rates (RR 1.10, 95% CI 0.95 to 1.27; I2=43%; 9 RCTs; 4,061 women). Additionally, moderate quality evidence suggests there is no relevant difference on miscarriage rates (RR=0.92, 95%CI=0.68-1.26, I2=6%, 8 RCTs, 988 clinical pregnancies; the quality of the evidence was downgraded because of imprecision).ConclusionsGood quality evidence from RCTs suggest that oral dydrogesterone provides at least similar reproductive outcomes than vaginal progesterone capsules when used for LPS in women undergoing embryo transfers. Dydrogesterone is a reasonable option and the choice of either of the medications should be based on cost and side effects.