A randomized trial of ovulation induction with two different doses of Letrozole in women with PCOS

To compare the effects of either a 5 or 7.5 mg daily dose of Letrozole in PCOS women undergoing ovulation induction and timed intercourse.

Prospective randomized trial.

Academic infertility care center.

Sixty-seven PCOS patients with infertility.

Patients were randomly divided into two groups and treated with either 5 mg/day (30 patients, group 1) or 7.5 mg/day (37 patients, group 2) Letrozole for 5 days starting from day 3 of the menstrual cycle. When the leading follicle reached 18 mm in diameter, ovulation was triggered by an injection of HCG and timed intercourse was advised thereafter.

The primary outcome measures were the number of follicles and days to reach mature follicle and the secondary endpoints were endometrial thickness, day 7 testosterone level, ovulation and pregnancy rates.

The mean age, BMI, duration of infertility and basal hormone levels in both groups were similar. There was no significant difference in the endometrial thickness (7.87 ± 1.67 vs 7.16 ± 2.04), the number of intermediate (0.83 ± 0.75 vs 0.62 ± 0.76) and mature follicles (1.13 ± 1.11 vs 1.22 ± 1.03) on days 12-14 between group 1 and 2, respectively. The days to reach mature follicle were similar in both groups (12.8 ± 1.36 vs 12.6 ± 1.22). Also there was no significant difference in the day 7 testosterone level and day 21 progesterone level between the two. Ovulation occurred in 90 and 89.2% of patients in group 1 and 2, respectively without a statistically significant difference. The pregnancy rate per first ovulatory cycle was 25.8% in group 1 and 21.2% in group 2 without significant difference. No OHSS was observed in either group.

The results of this study did not show any advantage to the use of 7.5 mg/day over 5 mg/day dose of Letrozole as the first line treatment for induction of ovulation in women with PCOS.