Abnormal endometrial peristalsis in frozen-thawed embryo transfer: risk factors and improvement of Atosiban treatment

A successful pregnancy after frozen embryo transfer cycles depends on proper coordination between the embryo and the uterus. In some cases, the uterus shows abnormal movements - called abnormal EPWs - which may make it harder for implantation. In this study, we analyzed medical data from over 7,500 women who had frozen embryo transfers. About 500 of them showed abnormal EPWs during an ultrasound check before embryo transfer. These women received a medication (Atosiban) that helps relax the uterus. We found that abnormal uterine movements can be caused by several factors. After receiving treatment, women with abnormal movements had pregnancy chances similar to those without the problem. The benefit was even greater when embryos were transferred at an early stage (day 3 embryos). This suggests that detecting and treating abnormal uterine movements could improve the chances of pregnancy for some women undergoing IVF, especially those receiving early-stage embryos.