A comparative study of letrozole and clomiphene citrate for ovulation induction in women with polycystic ovarian syndrome: a randomized controlled trial

Background: Effective ovulation induction is crucial in management of polycystic ovarian syndrome (PCOS) related infertility. Clomiphene citrate (CC) has long been the first line of treatment for inducing ovulation in women with PCOS. Letrozole, an aromatase inhibitor, has emerged as a promising alternative to CC for ovulation induction. The present study was aimed to compare efficacy and safety of letrozole versus CC for ovulation induction in women with PCOS. Methods: This study consists of 384 PCOS women, randomized into two groups: Letrozole (2.5 mg/day) and CC (50 mg/day), both administered from day 3 to day 7 of the menstrual cycle. The primary outcome was the ovulation rate, confirmed by serum progesterone levels >10 ng/ml. Secondary outcomes included clinical pregnancy rate, live birth rate, endometrial thickness, adverse effects, cost-effectiveness, and patient satisfaction. Participants were monitored through transvaginal ultrasound and serum progesterone measurements. Results: Ovulation was achieved in 76.0% of participants in the letrozole group compared to 55.2% in the CC group (p<0.001). Clinical pregnancy rates were significantly higher in the letrozole group (44.8%) compared to the CC group (28.1%) (p<0.001). Similarly, live birth rates were higher with letrozole (36.5% vs. 22.4%; p=0.002). Endometrial thickness was greater in the letrozole group (8.7 mm vs. 7.5 mm; p<0.001). Adverse effects, were significantly lower in the letrozole group. Conclusions: Letrozole is more effective than CC in inducing ovulation and achieving higher pregnancy and live birth rates in women with PCOS.