The effect of metformin use on pregnancy rates among polycystic ovary syndrome patients undergoing in vitro fertilization: A retrospective-cohort study

Background Metformin is widely used with gonadotropins by women with polycystic ovary syndrome (PCOS) during in vitro fertilization (IVF) to increase their chances of pregnancy. The aim of this study was to evaluate the efficacy of metformin in improving the rates of clinical pregnancy among women with PCOS undergoing IVF. Methods This was a retrospective cohort study of women with PCOS, aged 18–40 years, undergoing IVF during 2006–2012 at a University Hospital in Riyadh, Saudi Arabia. Baseline patient data including menstrual frequency, biochemical parameters such as fasting serum insulin (FSI) concentration, comorbidities, and the rates of ovulation and pregnancy were collected. Pregnancy rates were compared between the metformin and non-metformin groups. Results A total of 210 women with PCOS met the inclusion criteria and were included in the study. Of the 210 women with PCOS, 109 of them received metformin in addition to gonadotropins. Patients who received metformin were 16% less likely to be pregnant in comparison with those who did not receive metformin (OR = 0.840; 95% CI = 0.710–0.993; P = 0.0415), when controlled for baseline prolactin level, testosterone level, lipid panel, FSI concentration, fasting plasma glucose (FPG) concentration, comorbidities, duration of infertility, daily metformin dosage, and the previous use of clomiphene and/or leuprolide. Conclusions Metformin co-treatment during IVF may negatively affect pregnancy rates. Further well-designed, randomized, double-blind placebo-control clinical trials are needed to confirm the findings of this study.