Letrozole versus clomiphene citrate for ovulation induction in anovulatory women with PCOS: A randomized controlled trial.

OBJECTIVE To compare the efficacy of the 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 mono-follicular development and time to conception. RESULTS Mean endometrial thickness was 9.86 ±2.32 mm and 9.39 ± 2.06 mm with letrozole and clomiphene respectively (p = 0.751). Cumulative ovulation rate was 86.73 % & 85.21% with letrozole & clomiphene respectively (p =0.751). Pregnancy was achieved in 42.2% women in letrozole group and 20.0% in clomiphene group (p=0.04). Mono-follicular development was seen in 68.47% of ovulatory cycles in letrozole group compared to 44.89 % in clomiphene group (p=0.000). Mean time to achieve pregnancy was significantly shorter (log rank p = .042) with letrozole (9.65 weeks) than with CC (11.07). 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 due to high mono-follicular growth.