P-199: Comparison of Clomiphene Citrate and Letrozole Effect on Folliculogenesis in Polycystic Ovarian Syndrome Patients

Background: Polycystic ovarian syndrome (PCOS) which is the most common form of anovulatory infertility affects 5-10% women of reproductive age. Clomiphene Citrate (C.C) is the first line treatment in infertile women entering intrauterine insemination (IUI) cycle. For C.C resistant patients the second approach is aromatase inhibitors such as Letrozole. The aim of this study is to compare the effectiveness of C.C with Letrozole on folliculogenesis and pregnancy rate in PCOS women undergoing IUI cycles. Materials and Methods: Total of 207 IUI candidate women including 101 PCOS patients and 106 women with male factor infertility (controls) were selected. All women were matched by Age (20-35 years) and they were divided into normal- and over-weight (BMI=18.5-25 and 25-30 kg/m2, respectively) groups. Patients were given either C.C or Letrozole daily for 5 days followed by Gonadotropins. The number of follicles ≥15 mm, as a character for drug response, was monitored on day 10 of stimulation by trans-vaginal scans. Multiple linear regression analysis was performed. Results: The mean of mature follicle numbers in controls was significantly higher in comparison with PCOS patients (p=0.00), however in both groups, Letrozole showed more effect on achievement of follicles≥15. Patients with normal weight showed better response to ovulation induction cycles compare to women with BMI=25-30 (p=0.001). Pregnancy rate was 31 and 20% in PCOS and control groups, respectively. Conclusion: In PCOS patients the follicular response was significantly lower than that of control group. Aromatase inhibitors (Letrozole) can be more effective than C.C in PCOS patients since hyperandrogenism is one of the main features of disease and it affects on folliculogenesis. More study on molecular activity and pharmacogenetics of Letrozole is recommended.