Letrozole versus clomiphene citrate for ovulation induction in anovulatory women with polycystic ovarian syndrome: A randomized controlled trial

Objective To compare the efficacy of letrozole and clomiphene citrate (CC) for ovulation induction in infertile women with polycystic ovarian syndrome (PCOS). Methods In this assessor blind, randomized controlled trial, 90 infertile women with PCOS were randomized to receive either letrozole or CC for ovulation induction in incremental doses for a maximum of three cycles. Main outcome measures studied were endometrial thickness, ovulation rate, pregnancy rate, rate of monofollicular development, and time to conception. Results Mean endometrial thicknesses were 9.86 ± 2.32 mm and 9.39 ± 2.06 mm with letrozole and CC, respectively (P=0.751). Cumulative ovulation rates were 86.7% and 85.2% with letrozole and CC, respectively (P=0.751). Pregnancy was achieved in 42.2% of women in the letrozole group and 20.0% of women in the CC group (P=0.04). Monofollicular development was seen in 68.4% of ovulatory cycles in the letrozole group compared with 44.8% in the CC group (P=0.000). Mean time to achieve pregnancy was significantly shorter (log rank P=0.042) with letrozole (9.65 weeks) than with CC (11.07 weeks). Conclusion Letrozole is a better alternative for ovulation induction in anovulatory women with PCOS as pregnancy rates are higher, time to pregnancy is shorter, and chances of multiple pregnancy are less because of high monofollicular growth. Synopsis Letrozole is a better alternative for ovulation induction than clomiphene citrate.