A randomized trial comparing the ovulation induction efficacy of clomiphene citrate and letrozole

Letrazole is an aromatase inhibitor, which is useful in ovulation induction. However, evidence on its efficacy over clomiphene citrate, which is the first of drug used for therapy of anovulation, is insufficient in Indian patients.

To compare the efficacy of letrozole and clomiphene citrate in attaining optimal follicular growth.

The study was conducted in the infertility clinic of Mahatma Gandhi Medical College and Research Institute, Pondicherry, India from June 2008 to December 2009. Fifty women with ovulatory dysfunction as a cause of infertility were enrolled and randomized into two groups of 25 each. Group 1 received clomiphene citrate in incremental dose from 50 mg up to150 mg and Group 2 patient received letrozole in incremental dose from 2.5 mg to 7.5 mg, depending upon the ovulation response. In both the groups, number of follicles, diameter of large follicle, endometrial thickness, and serum estradiol and pregnancy rate were compared. The data from both groups are represented as mean and standard deviation and statistically compared using Student's t test.

The number of follicles (1.89 ± 0.9 vs 1.18 ± 0.393) and serum estradiol levels (437.5 ± 293.7 pg/mL vs 291.82 ± 59.86 pg/mL) were higher in Group 1, while follicular diameter (20.67 ± 0.970 mm vs. 20.76 ± 0.903 mm) and endometrial thickness (8.5 mm vs.7.4 mm) were similar in both the Groups.

Although letrozole is used for ovulation induction in anovulatory infertility, no significant beneficial effects of letrozole compared to use of clomiphene citratewere observedin ourstudy. Hence, we concur with the use of clomiphene citrate as the first line of drug for ovulation induction in Indian population and warrant larger size studiesto further validate our results.