Letrozole indifferent dosages for ovulation induction in patients with polycystic ovarian syndrome not responded to clomiphene citrate

Objective: To choose the suitable dose of letrozole (LTZ) for ovulation induction in anovulatory patients with polycystic ovarian syndrome (PCOS). Design: Prospective randomized study. Setting: OB/GYN department, Benha Teaching Hospital, Benha, Egypt. Patient(s): 120 anovulatory infertile women with PCOSthatwerenot responded to clomiphene citrate(CC) stimulation for one cycle. Intervention(s): The studied patients were randomly divided into 3 groups (A, B, C). LTZ was given in increasing dosage from group "A" to group "C". Materials and Methods: In group "A": the dose of letrozolewas 2.5 mg / day, in group "B": it was 5 mg / day, and in group "C": it was 7.5 mg per day. The LTZ was given from day 2-6 of the menstrual cycle. Main outcome measures were: ovulation rate, number of mature follicles, endometrial thickness and pregnancy rate. Results: On increasing the LTZ dosages between the three groups (A, B and C),only the mean number of dominant follicles and the numbers of ovulatory cycles were significantly increasing; (P=0.025) and (P=0.012), respectively. On the other hand, the relation was insignificant for mid-cycle endometrial thickness and the pregnancy rate; (P=0.542) and (P=0.765), respectively.The differences in the age, duration of infertility and body mass index (BMI) were not statistically significant between the three groups. Conclusion:Letrozole is superior to CC in ovulation induction for patients with PCOS. Increasing the letrozole dosage will increase the number of mature follicles and ovulation rate, but has no effect on pregnancy rate.Until studies with large sample sizes are available, LTZ may be used as the first or second option for ovulation induction and to start with 2.5 mg per day and increase the dose gradually in the subsequent cycles if there is no adequate response.