The Impact of Letrozole Versus Clomiphene Citrate on Uterine Blood Flow in Patients with Unexplained Infertility

OBJECTIVE To compare the effectiveness of letrozole and clomiphene citrate (CC) on uterine blood flow rate in patients with unexplained infertility. MATERIALS AND METHODS In this randomized clinical trial 90 women with unexplained infertility referred to a university clinic from January 2011- December 2013 were enrolled. Thirty patients were randomized for letrozole, 30 patients for CC and 3o patients for control group. On the day 3 of cycle the patients were given letrozole 2.5mg/day or CC 100 mg /day orally or did not receive any treatment. Resistance index (RI) and pulsatility index (PI) of uterine artery were calculated and chemical pregnancy rate was evaluated. RESULTS Mean age was 26.4±3.2 (20-33) and mean BMI was 26.3± 3.2. After treatment using ultrasonography the Resistance index (RI) and Pulsatility index (PI) showed no significant difference among three groups (P > 0.05). Pregnancy rate in letrozole group (58%) was more in comparison to CC (53.6%) and control groups (46%) but the difference was not significant (P > 0.05). CONCLUSION Our study showed that letrozole and clomiphene citrate have comparable impact on uterine blood flow and pregnancy rate in women with unexplained infertility.