Recurrent Implantation Failure: A Comprehensive Summary from Etiology to Treatment

Recurrent implantation failure (RIF) is a complex condition characterized by the failure to achieve pregnancy after transferring at least three good-quality embryos in women under 40. The document explores various risk factors, including high BMI, smoking, alcohol, and stress, and highlights the role of uterine natural killer (uNK) cells in maternal-fetal immune tolerance and angiogenesis. Imbalances in immune cells, thrombophilias, and anatomical abnormalities like fibroids and endometriosis are also discussed. Treatment strategies include lifestyle changes, medical interventions, and therapies like intralipid therapy, lymphocyte immunization, and anticoagulants. Promising treatments such as platelet-rich plasma (PRP), granulocyte colony-stimulating factor (G-CSF), and antibiotics for chronic endometritis are noted, but further research is needed to establish effective protocols.