Materials and Methods: This randomized controlled clinical trial was conducted in a University Clinic from November 2017 to January 2019. A total of 120 candidates entered the study, who were assigned to intervention (n=60) and control (n=60) groups. All subjects underwent controlled ovarian stimulation using letrozole 2.5 mg/BD on a day between 3 and 7 of the cycle. Then, the sonographic monitoring was started from day 8 of the cycles, followed by injecting human chorionic gonadotropins (HCG) 100001U intramuscularly when 1-2 follicles reached 18 mm in diameter. Approximately 36-38 hours afterward, IUI was done and a B-HCG test was performed after 15 days as well. In addition, luteal phase support was performed with the vaginal progesterone 400 mg twice daily for 15 days. In the intervention group, on day 3 of the cycle endometrial cavity on the posterior wall was scratched with the vaginal cannula No. 4 by a single infertility specialist in addition to the routine procedure. The chemical and clinical pregnancy rates were the main outcome measurements.

Results: The overall clinical pregnancy rates were 11/59 (18.6%) and 10/59 (16.9%) in intervention and control groups, respectively (P=0.810). Further, the abortion rates were 1/59 (1.7%) and 3/59 (5.1%) in intervention and control groups, respectively (P=0.303). Eventually, no cases of ectopic pregnancy were observed in either group.

Conclusions: Based on the findings of this study, endometrial scratch by pipelle cannot improve pregnancy rate in the early proliferative phase.