Background: Endothelial dysfunction can influence fertility rate in women with polycystic ovary syndrome (PCOS) as flow mediated dilatation (FMD) is impaired in patients with the disease. The aim of this study was to compare two methods of ovulation induction by letrozole or letrozole plus human menopausal gonadotropins (HMGs) in infertile women with PCOS who were resistant to clomiphene citrate based on brachial artery ultrasound findings.

Methods: In this double -blind randomized clinical trial, 59 infertile women who had the inclusion criteria for PCOS were evaluated in the Infertility Clinic of Shariati Hospital in Tehran, Iran in 2010-2011. The patients were assigned to two letrozole and letrozole plus HMG groups and were evaluated for FMD in the brachial artery by transvaginal ultrasonography. Later, the values were recorded and analyzed statistically.

Results: In the letrozole group, infertility treatment was successful in 15 (57.7%) but it failed in 11 (42.3%) patients. In letrozole plus HMG group, the treatment was successful in 18 (54.5%) while it failed in 15 (45.5%) patients. The mean FMD values in the groups with successful and unsuccessful treatment results were 19.42±10% and 18.57±7.2%, respectively, but the difference was not statistically significant (P=0.712). Moreover, the average endometrial thickness in groups with successful and unsuccessful treatment results were 8.4±1.3 mm and 9.8±3.9 mm, respectively but the difference was not significant either (P=0.06).

Conclusion: In infertile women with polycystic ovary syndrome that are resistant to clomiphene, letrozole or letrozole combined with gonadotropin can be equally effective for ovulation induction.