Letrozole for Induction of Ovulation in PCOS Patients: Resistant to Clomiphene Citrate

Abstract

Objective To assess the efficacy of aromatase inhibitor letrozole for induction of ovulation in anovulatory polycystic ovary syndrome (PCOS) patients in whom clomiphene citrate (CC) treatment was unsuccessful. Design Prospective, nonrandomized, interventional, crossover trial, using anovulatory PCOS infertile patients previously treated with clomiphene citrate as their own historic controls. Setting Center for Assisted Reproduction (CARE), Department of Obstetrics and Gynecology, Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorders (BIRDEM), Dhaka, Bangladesh. Patients 60 anovulatory PCOS infertile patients who received 150 mg of clomiphene citrate for at least 4 cycles on days 2 to 6 of the cycle with an unsatisfactory outcome (No mature follicle and/or endometrial thickness of equal or less than 0.7 cm) were the target population. Intervention 5.0 to 7.5 mg of letrozole was given orally on days 2 to 6 of the cycle. Main outcome measures: Number and size of mature follicles, endometrial thickness and occurrence of ovulation. Results There was a statistically significant increase in the follicular size and endometrial thickness after the administration of letrozole. Ovulation occurred in 38 patients (63.33%) in the letrozole treated cycles. Most of developed follicles (68.42%-26 patients) were multiple and majority patients (63.16%) responded to the higher 7.5 mg dose. Conclusion Oral administration of letrozole is an effective agent for ovulation induction in clomiphene citrate resistant PCOS patients.