Low-dose aspirin for infertile women with thin endometrium receiving intrauterine insemination: A prospective, randomized study

Purpose: The objective was to evaluate the effect of aspirin on infertile women with thin endometrium. Methods: Patients who had thin endometrium (less than or equal to 8 mm) and intrauterine insemination were divided into the aspirin and nonaspirin groups. Endometrial pattern (trilaminar and nontrilaminar) and thickness, the pulsatility index (PI) and resistance index (RI) of the uterine artery, spiral artery and ovarian dominant follicles, and pregnancy rates of both groups were measured. Results: A total of 114 and 122 women were included in the aspirin and nonaspirin groups, respectively There were significantly higher percentages of trilaminar endometrium (46.5% vs. 26.2%) and pregnancy rate (18.4% vs. 9.0%) after aspirin therapy. There was nonsignificant difference in the endometrial thickness, and PI/RI values of the uterine artery, spiral artery, and ovarian dominant follicle between both groups. Conclusions: Higher pregnancy rate and better endometrial pattern were achieved in patients with thin endometrium after aspirin administration. Aspirin therapy could not significantly increase the endometrial thickness and the resistance of uterine and ovarian flow.