A matched study to determine whether low-dose aspirin without heparin improves pregnancy rates following frozen embryo transfer and/or affects endometrial sonographic parameters

Purpose: The objective of the matched, controlled study was to determine whether law-dose aspirin therapy without heparin improves pregnancy rates following frozen embryo transfer. Methods: Thirty-six women who did not achieve a pregnancy following fresh embryo transfer and who had frozen embryos available for another transfer were included. Eighteen women were treated with 81 mg aspirin from day 2 of the cycle through pregnancy resting. if the beta-human chorionic gonadotropin level was positive, aspirin was continued through the pregnancy. Eighteen women were not given aspirin. The mean outcome variables were pregnancy and implantation rates. Results: The clinical pregnancy rare in the aspirin group was 11.1%, compared with 33.3% for the controls, and implantation rates were 2.9 and 10.9%, respectively, Conclusions: No positive effects of low-dose aspirin therapy on pregnancy rates following frozen embryo transfer were observed.