Efficacy of Clomiphene Citrate and Letrozole in Induction of Ovulation in Patients of PCOS: A Randomized Prospective Clinical Trial

Ovulatory dysfunction is an important cause of infer-tility and PCO remains one of its leading causes. Clo-miphene citrate has been traditionally used as the drug of choice in treating women with an ovulatory infer-tility. In the last decade letrozole, an aromatase inhibi-tor has emerged as an alternate ovulation inducing agent. Objectives:   The purpose of this study was to compare the efficacy of letrozole with clomiphene citrate. The primary outcome measure was the occurrence of ovu-lation, mature follicles and endometrial thickness. Al-though measuring pregnancy rate was not our main objective but we found that pregnancy outcome was better in the letrozole group than the clomiphene gro-up. Methodology:   In this prospective randomized clinical trial 140 women with Polycystic ovarian disease in the  WHO group II were randomized to receive either letrozole or clomiphene citrate. Patients were rando-mly divided into two groups by lottery and treated with 2.5 mg / day or 150 mg / day for 5 days starting from day 3 of menstruation. Data was managed using SPSS version 17. Results:   The mean age of the patients was 26.3 ± 4.1 years old (range, 22 – 35) and the mean duration of infertility was 3.66 ± 1.9 years (range, 1 – 9). The mean endometrial thickness in letrozole group was 10.42 ± 0.487 mm and in clomiphene citrate the mean endometrial thickness was 8.11 ± 6.2. The number of mature follicles although lower in letrozole but single leading follicle size > 18 mm were more in group A than group B, p-value < 0.05. The secondary outcome i.e. pregnancy rate was greater in letrozole group, i.e. 36 (51.4%) as compared to clomiphene i.e. 22 (31.4%), p-value < 0.05. Conclusion:   Letrozole although it induces fewer ovulatory follicles but endometrial thickness at the time of implantation and pregnancy rate is greater than clomiphene citrate. Keywords:   Ovulation induction, endometrial thickness, letrozole, Clomiphene citrate.