Effect of preconceptional metformin on abortion risk in polycystic ovary syndrome: a systematic review and meta-analysis of randomized controlled trials

Objective: To evaluate the effect of pregestational metformin administration on abortion risk in polycystic ovary syndrome (PCOS) patients. Design: Systematic review and meta-analysis. Setting: Academic Department of Obstetrics and Gynecology in Italy. Patient(s): Women affected by PCOS receiving pregestational metformin. Intervention(s): Systematic review of randomized controlled trials (RCTs) published up to June 2008 and subsequent meta-analysis. Main Outcome Measure(s): Abortion rate. Result(s): Seventeen RCTs were included in the final analysis. Overall, no effect of the metformin administration was detected on the abortion risk. No statistically significant effect of metformin on the abortion risk was observed in any comparison when subgrouping the RCTs according to received treatment. Conclusion(s): Metformin has no effect on the abortion risk in PCOS patients when administered before pregnancy. (Fertil Steril (R) 2009;92:1646-58. (C) 2009 by American Society for Reproductive Medicine.)