Abstract
Letrozole was compared with clomiphene citrate (CC) as a first-line treatment for ovulation induction in women with polycystic ovaries (PCOs). A total of 106 women with primary infertility and a diagnosis of PCOs were randomized to receive either 100 mg CC (n = 55) or 2.5 mg letrozole (n = 51) daily for 5 days. Human chorionic gonadotrophin (hCG) at a dose of 10 000 IU was administered when at least one follicle with a mean diameter ≥ 18 mm was observed using transvaginal ultrasound. The number of mature follicles was significantly lower, but endometrial thickness and ovulation and pregnancy rates were significantly higher in the letrozole group than in the CC group. In conclusion, letrozole is associated with a higher pregnancy rate than CC in PCO patients and may have a role as a first-line treatment for anovulatory patients with PCOs.