Depending on the definition used, about 10% of the couples who were treated with in vitro fertilization (IVF) will experience recurrent implantation failure (RIF), whilst many of them who can achieve implantation, will be disappointed in early pregnancy loss. Couples, who were unable to get pregnant, though getting both immunomodulation therapy used and many high-quality embryos, want to know the reasons why they actually failed.
When physicians encounter these couples, they try to find something to improve success rate, and sometimes they can choose several strategies for these couples without a solid explanation. Indeed, these strategies include several immunomodulation therapy. However, they are choosing not theoretical, but empirical immunomodulation therapy.
To modulate the immune response in between the maternal endometrium and the implanting embryo, physicians are awakening interest in this field. The first step for this process is to understand of how a mother transfers a genetically alien embryo immunologically, and what happened at the spot of the invasion of maternal tissues by the embryo.
One of the mechanisms that help to understand the idea of the balance between pro- and anti- inflammatory conditions characterized by a palette of cytokines and immune cells such as T-helper cells and natural killer cells, which may influence the fate of implanting embryo. Although it is clear that the function of these cytokines, repeated IVF failure may gradually resolved using concepts of immune response such as immune rejection and immune tolerance in between the uterine endometrium and the embryos implanted or implanting.
Many studies have tried to prove the effectiveness of different methods of immunomodulation therapy, which are heterogeneous in design, methods, interventions and study populations, hinder their explanation and understanding. Physicians need a thorough understanding of both mechanisms and modulations about human embryo implantation when they try to make progress in this area. Therefore, immunomodulation therapy fascinates physicians who encounter couples with RIF. The current use of immunomodulation therapy supported by published evidence and will be useful both to couples suffering from RIF and physicians who are faced of these couples.
Although RIF in the field of ART can cause a variety of reasons, a respond that women might reject embryos immunologically is well known as the cause of RIF. Lately, it has been shown that the balance of T-helper 1 (Th1), and T-helper 2 (Th2), may be a useful marker for detection of immunological rejection between endometrium of infertile women and transferred embryos within the ART treatment.
Furthermore, this ratio can be used to select the ART treatment strategy for the couples with RIF. Immunological rejection like RIF is not the majority, but this cause can be solved by an appropriate approach.