Publication:

Use of letrozole versus clomiphene citrate combined with gonadotropins for ovulation induction in infertile women with polycystic ovary syndrome: a pilot study

Background The aim of the study was to evaluate the efficacy of letrozole and clomiphene citrate (CC) in gonadotropin-combined for ovulation stimulation in women with polycystic ovary syndrome (PCOS). It was a prospective pilot study.

Methods This prospective trial included 124 patients of infertile women with PCOS. Letrozole dose of 5 mg/day (n = 65) or a CC dose of 100 mg/day (n = 59) was given on day 3 to day 7 of the menstrual cycle, combined with gonadotropin i.e. follicle stimulating hormone (FSH) at a dose 75 IU every day starting on day 7 and continued to day 9. Main outcome measures were occurrence of ovulation, number of mature follicles, serum estradiol (E2) and endometrial thicknesses on the day of human chorionic gonadotropin (hCG), and pregnancy rates.

Results The clinical profile including mean age, duration of infertility, BMI, baseline FSH, LH and E2 of patients belonging to both groups were comparable. The numbers of mature follicles (4.3±0.3 vs. 2.9±0.7) were significantly higher in letrozole+FSH group. Serum E2 levels on the day of hCG (301.78±85.7 vs. 464.7±72.9 pg/mL) were significantly lower in the letrozole+FSH group. Significant differences were found in endometrial thickness measured on the day of hCG in letrozole+FSH group (p=<0.0001). The rate of ovulation was higher in letrozole+FSH group and it was marginally statistically significant (p=0.040). The rate of pregnancy was slightly greater in the letrozole+FSH group (17.85% versus 13.33%), although not statistically significant.

Conclusions Letrozole in combination with FSH appears to be a suitable ovulation inducing agent versus CC with FSH in PCOS. This combination may be more appropriate in patients who are particularly sensitive to gonadotropin.