Background: Metformin, an insulin-sensitizing agent, has been used successfully as the first-line drug to induce ovulation in women with polycystic ovary syndrome. There are, however, very few studies evaluating metformin treatment in women with clomiphene citrate (CC)-resistant polycystic ovaries (PCO).
Methods: Twenty infertile Chinese women aged <40 years, who had ultrasound features of PCO and remained anovulatory on CC, were randomized by computer using the sealed envelope method to receive placebo or metformin 500 mg three times a day for 3 months. Hormonal and metabolic profiles were determined before the therapy and were repeated after 3 months for women who failed to become pregnant within this period. Clomiphene was then added for one cycle to those women who did not ovulate after taking placebo or metformin alone.
Results: The median ovulation rate in the placebo group was 0% (range: 0--50%) after placebo only and 6.9% (range: 0--50%) after placebo and CC, whereas the corresponding rates in the metformin group were 0% (range: 0--22%) and 0% (range: 0--22%) respectively. There was no improvement in the ovulation rate despite a significant reduction of body mass index, serum testosterone and fasting leptin concentrations in the metformin group.
Conclusions: Metformin treatment may result in successful ovulation only in certain subgroups of these women.