Does metformin induce ovulation in normoandrogenic anovulatory women?

Objective This study was undertaken to evaluate the efficacy of metformin in women with anovulation who do not have evidence for hyperandrogenism and classic polycystic ovary syndrome. Study design A randomized trial of metformin (1500 mg daily) and placebo in 24 anovulatory women was undertaken for 3 months. Assessments of changes in hormone levels and insulin sensitivity were carried out. Abnormal hormonal values were defined by levels exceeding the range in normal ovulatory controls. Results Anovulatory women had normal androgen levels and luteinizing hormone but had higher serum insulin and lower insulin sensitivity compared with controls. Over 3 months, there were 16 ovulatory cycles with metformin and only 4 with placebo (P< .05). Success of ovulation did not correlate with changes in androgen, insulin, or insulin sensitivity parameters. Conclusion Metformin may be useful for inducing ovulation in anovulatory women who do not have hyperandrogenism. This effect may be independent of a lowering of androgen or insulin levels.