The Effect of Metformin Therapy for Preventing Gestational Diabetes Mellitus in Women with Polycystic Ovary Syndrome: A Meta-Analysis

Objective This study was to analyze the efficacy of metformin intervention in preventing gestational diabetes mellitus (GDM). Methods A systematic review and meta-analysis of clinical trials or observational studies of metformin intervention in preventing symptoms of GDM during pregnancy were performed. Medline, Embase, and Cochrane Library were searched through to now. The main evaluated primary outcomes were incident of GDM, miscarriage, preterm delivery, and neonatal mortality. The evaluated secondary outcomes were mean difference of gestational age at birth and birth weight between metformin group and control group. Results We included 6 studies including 3 randomized clinical trials (RCTs), 2 observational studies, and 1 non-RCT in our meta-analysis. A total of 643 patients were enrolled for a follow-up study with continued metformin therapy (n = 341) or not (n = 302) during pregnancy. Metformin therapy reduced the proportion of patients developing GDM (log Odds Ratio: -1.27; 95 %CI: -2.24 to -0.30) but had no significant effect on reducing the proportion of abortion, preterm delivery, and neonatal death in pregnant women with polycystic ovary syndrome (PCOS). Also, it did not cause a significant difference in gestational age at birth and birth weight in metformin group versus control/placebo group. Conclusions Metformin was associated with less frequent GDM development than control diets, suggesting that it is the appropriate intervention to be prescribed to prevent GDM in patients with PCOS.