Effect of endometrial injury on pregnancy outcomes in infertile women undergoing intrauterine insemination.

Objective: One of the most common treatments for infertility is intrauterine insemination (II). The objective of this study was to determine the effect of endometrial injury on pregnancy outcomes in unexplained infertility in women undergoing II. Materials and Methods: In this randomized clinical trial, 122 women with unexplained infertility who were referred to Shariati Hospital from 2018 to 2020 were enrolled. They underwent ovulation induction using letrozole and gonadotropins. On day 9 of stimulation, they were randomly assigned to two similar groups of the same size. The first group underwent endometrial local injury by pipelle endometrial sampling, and the second group (control group) received no intervention. Only 1 II cycle was performed for each patient. Patients with negative pregnancy outcomes were followed up for 3 months. Endometrial thickness, dominant follicle count, chemical and clinical pregnancy rate, miscarriage rate, and spontaneous pregnancy rate after the II cycle were compared between the two groups. Results: Endometrial thickness, dominant follicle count, chemical and clinical pregnancy rate, and miscarriage rate in the same II cycle were not different between the two groups (p>0.05). However, the spontaneous pregnancy rate after the II cycle was significantly higher in the endometrial injury group (p=0.02). Conclusion: Endometrial injury increases pregnancy rates in later cycles but not in the same II cycle.