Randomized controlled trial of different doses of metformin for ovulation induction in infertile women with polycystic ovary syndrome

Abstract

To compare the efficacy of 1000 mg and 1700 mg of metformin on ovulation induction in polycystic ovary syndrome (PCOS) women. A randomized controlled trial was conducted at Ramathibodi Hospital, Mahidol University, Bangkok, Thailand of 60 PCOS women diagnosed by Rotterdam criteria. Group A (30 women) and B (30 women) received 1000 mg and 1700 mg/day of metformin, respectively. Clomiphen citrate 50-150 mg per day for 5 days was added, if no dominant follicle developed. The main outcome measures were ovulation and pregnancy rates, fasting insulin (FI), testosterone (T), androstenedione (ADD) and DHEAS before and 4 weeks after metformin. The ovulation rate did not differ between the groups (84.8% vs 87.7% between groups A and B, P=NS). Most of the women developed one follicle (91% in group A and 88.2% in group B, P=NS). The pregnancy rate in group A (46.4% per woman and 12.4% per ovulatory cycle) did not differ from that in group B (51.9% per woman and 13.2% per ovulatory cycle, P=NS). With regard to dosages, the ovulation rate in PCOS women without insulin resistance (IR) was significantly higher than those with IR. FI, T and ADD were significantly decreased after 4 weeks of metformin in both groups. 1000 mg of metformin had as high efficacy as 1700 mg on induction of ovulation and pregnancy in PCOS women.