Evidence-Based and Potential Benefits of Metformin in Polycystic Ovary Syndrome: A Comprehensive Review

In 2008, a comprehensive review of metformin's use in treating Polycystic Ovary Syndrome (PCOS) presented evidence of its benefits across various symptoms and complications of the syndrome. Metformin was found to be effective in restoring regular menstrual cycles in 62% of women with PCOS and oligoamenorrhea and was more effective than oral contraceptives in reducing insulin and triglyceride levels. However, it was less effective for menstrual regulation compared to oral contraceptives and had limited evidence supporting its benefits for hirsutism, diabetes prevention, and weight loss. The review suggested metformin as a first-choice treatment for oligomenorrhea when oral contraceptives were contraindicated and for anovulatory infertility. While metformin did not significantly increase pregnancy and live birth rates, it was beneficial as a pretreatment before clomiphene citrate (CC) and when combined with letrozole, though not with rosiglitazone. The review also indicated that metformin could improve fertility outcomes in PCOS patients, with its effectiveness depending on the treatment approach and patient characteristics. Metformin was also associated with potential cardiovascular benefits and a reduction in the risk of type 2 diabetes mellitus. However, the review called for more research to establish the clinical significance of these findings and to evaluate the impact of treatments on quality of life.