Insulin resistance and fertility in polycystic ovary syndrome

Polycystic Ovary Syndrome (PCOS) represents a common endocrinopathy, with anovulation and hyperandrogenism as cardinal symptoms. In recent years it has been recognized that insulin resistance is an intrinsec feature of the disorder and plays a central role in pathogenesis. PCOS is associated with important reproductive morbidity as shown by high prevalence of anovulatory infertility, spontaneous abortion, gestational diabetes and preeclampsia. The association of insulin resistance with this reproductive pathology has been well documented. Due to major implication of insulin resistance in PCOS pathogenesis, insulin reduction strategies were studied as a possible treatment for infertility in PCOS patients. Weight loss, even modest was proved to be a simple and efficient method to improve reproductive parameters in PCOS patients and should be recommended to all overweight and obese patients with infertility. Metformin was showed to induce ovulation, at least in a subset of patients with PCOS, but there are not unequivocal proves concerning its efficacy for pregnancies and live-birth rate, mainly because few trials studied this aspect. Therefore there are not enough evidences to recommend metformin for infertility treatment in PCOS. Few small studies with newer thiazolidindiones suggest their efficacy for ovulation induction, but further extensive studies are needed to confirm these results. In conclusion, reduction of insulin resistance was proved to ameliorate ovulation rate in PCOS patients, but strong evidences to sustain the utility of insulin-sensitizing drugs as a therapeutic option for infertility are lacking. Future studies are needed to elucidate these aspects and to characterize the particular subtype of patients with higher probability to respond to this treatment.