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.