Letrozole versus Clomiphene Citrate in Patients with Anovulatory Infertility

Objective: To compare the effectiveness of letrozole and clomiphene citrate (CC) in patients with anovulatory infertility. Design: Open, prospective, randomized, parallel group, multicentric, comparative trial. Setting: Outpatient clinics of infertility centers in India. Patient(s): Fifty-five patients with anovulatory infertility were recruited. Twenty-seven patients (59 cycles) were given letrozole and twenty-eight patients (68 cycles) were given CC. Both drugs were given orally on days 3-7 of menstrual cycle. Intervention(s): Letrozole, CC, ovulation induction, vaginal micronized progesterone, IUI. Main outcome measure(s): Occurrence of ovulation, endometrial thickness and pregnancy rates. Result(s): Ovulation occurred in 77.9 % (46/59) of letrozole cycles and in 80.9 % (55/68) of CC cycles. The mean endometrial thickness on the day of human chorionic gonadotropin administration was 9 mm in letrozole group and 8.76 mm in the CC group. Pregnancy rate per cycle was 11.9 % (7/59) in the letrozole group and 8.8 % (6/68) in the CC group. Conclusion(s): Letrozole and CC have comparable effectiveness in anovulatory infertility patients. Letrozole may be an acceptable alternative to CC as an ovulation-inducing drug.