Efficacy of metformin on ovulation induction in Asian women with polycystic ovary syndrome.

The aim of this study was to assess the efficacy of metformin on induction of ovulation in Asian women with clomiphene citrate (CC)-resistant polycystic ovary syndrome (PCOS). Twenty PCOS women who did not respond to CC were enrolled in the study. All received 500-1500 mg/day of metformin for 4 weeks. If no dominant follicle was observed with monitoring by transvaginal ultrasound, 50-150 mg of CC per day for 5 days were added. Timing of sexual intercourse was determined or intrauterine insemination was carried out 36 h after administration of human chorionic gonadotropin. A total of six cycles, pregnancy or anovulation despite taking 150 mg of CC were considered as completion of the study. Blood samples were obtained before and at the end of the 4th week of treatment for hormonal assay. Ovulation was observed in 68 (89.5%) of 76 cycles, of which 34 (44.7%) occurred with metformin alone. Twelve women conceived; therefore, the pregnancy rate was 17.6% per ovulated cycle and 60% per woman. One (8.3%) had an abortion. Four women had minimal adverse effect, but one experienced a severe gastrointestinal effect during the fourth cycle. Insulin and androstenedione levels were significantly decreased after 4 weeks of treatment. In conclusion, these series demonstrated the excellent efficacy of metformin on induction of ovulation and pregnancy in Asian women with CC-resistant PCOS.