Objective: To compare the efficacy of metformin and clomiphene citrate (CC) therapies for ovulation induction in anovulatory infertile women with polycystic ovary syndrome (PCOS).
Methods: A total of 69 consecutive infertile, anovulatory women with PCOS were enrolled in this prospective, non-randomized trial. The women were prescribed either 1,700 mg/day metformin or CC with a starting dose of 50 mg/day up to 150 mg/day for a period of six consecutive cycles.
Results: Metformin and CC groups were followed for a total of 136 and 94 cycles, respectively. Metformin group had lower rates of ovulation when compared with CC group (32.3 vs. 60.6%, respectively; p = 0.004). There was no statistical difference in pregnancy rates per cycle between the treatment groups (8 vs. 11.7%, respectively; p = 0.33) leading to similar cumulative pregnancy rates (36.6 vs. 35.4%, respectively; p = 0.45). No difference was observed among the abortion rates (10 vs. 10%, respectively; p > 0.05) between the groups.
Discussion: Although metformin and CC are two effective first-line approaches for improving pregnancy rates in anovulatory PCOS women, CC is associated with higher rates of ovulation.