Ultrasonographic markers of endometrial receptivity of letrozole and clomiphene citrate in unexplained infertile women

ObjectiveTo compare endometrial receptivity of letrozole and clomiphene citrate.Study designA prospective comparative study.Subjects120 women with unexplained infertility undergoing superovulation.InterventionSixty patients underwent ovulation induction using 5 mg letrozole compared with another 60 patients using 100 mg clomiphene citrate.Main outcomeThe endometrial thickness, the endometrial volume, uterine artery and spiral artery Doppler indices at 7 days after HCG administration.ResultsThe mean age, parity and duration of infertility in both groups of patients were similar. There was a significant difference in the endometrial thickness, endometrial volume, and spiral artery Doppler indices between the two groups one week after HCG administration. No difference was found in the uterine artery Doppler indices in both groups. The pregnancy rate was higher in the letrozole group but it was statistically insignificant.ConclusionLetrozole (5 mg) showed a significantly better endometrial response than 100 mg of clomid.