Letrozole vs. clomiphene citrate in patients with ovulatory infertility

ObjectiveTo compare the effectiveness of letrozole and clomiphene citrate (CC) in ovulatory patients with borderline male factor infertility, early stage endometriosis, and unexplained infertility.DesignProspective quasi-randomized trial.SettingUniversity infertility clinic.Patient(s)Forty-six consecutive patients with ovulatory infertility were recruited. Twenty-five patients (67 cycles) were given CC and 21 patients (52 cycles) were given letrozole. Both drugs were given orally on days 3–7 of menses.Intervention(s)Letrozole, CC, ovulation induction, IUI, timed intercourse.Main Outcome Measure(s)Number of follicles, endometrial thickness, and pregnancy rates.Result(s)The median serum E2 concentration on the day of hCG administration in the letrozole and CC groups were 191.5 pmol/L and 476.0 pmol/L, respectively. The median endometrial thickness on the day of hCG were 8 mm in both groups. Ovulation occurred in 81% (42/52) of the letrozole-treated and 85% (57/67) of the CC-treated patients. Pregnancy rate (PR) per cycle was 9% (5/52) in the letrozole group and 12% (8/67) in the CC group.Conclusion(s)Letrozole and CC have comparable effectiveness in ovulatory patients with borderline male factor infertility, early stage endometriosis, and unexplained infertility.