Clinical inquiries. Do insulin-sensitizing drugs increase ovulation rates for women with PCOS?

■ EVIDENCE-BASED ANSWER Short-term use of metformin (Glucophage) improves ovulation rates for women with polycystic ovary syndrome (PCOS) (strength of recommendation [SOR]: A, based on systematic reviews of randomized controlled trials [RCT]). Metformin also decreases menstrual irregularities (SOR: B, extrapolated from a systematic review). When added to clomiphene, metformin increases ovulation and pregnancy rates when compared with clomiphene alone (SOR: A, systematic review). Thiazolidinediones (TZDs) improve ovulation rates as well (SOR: B, based on low-quality RCTs). Research of longer duration including the key outcomes of pregnancy and birth rates, is needed to clarify the appropriate use of insulinsensitizing drugs for PCOS.