Recurrent Implantation Failure from an Immunological Point of View

Introduction: Repeated implantation failure (RIF) is one of the main challenges in modern infertility treatments. Although assisted reproductive technology (ART) has undergone a lot of progression over the last recent years, some women still experience implantation failure after several embryo transfers (ET). Disruption of the mother's immunologic tolerance towards the fetus is one of the risk factors that increases the possibility of rejection the semi-allogeneic embryo by the mother’s immune system and causes failure of embryo implantation. Studies have shown that immunomodulatory treatment approaches, if used in a timely and appropriate manner, have promising results in improving pregnancy outcomes and live birth rates in this group of women. This review focuses on changes in the immune system and the use of immunomodulatory treatments in women with recurrent implantation failure. Conclusion: It seems that the appropriate use of immunologic tests and proper immunomodulatory treatments can manage IVF failure after repeated embryo transfers.