Implantation Failure

Recurrent implantation failure (RIF) is generally defined as failure to achieve a clinical pregnancy after two or more transfers of good-quality embryos. Causes can be embryo-related (chromosomal abnormalities are the most common), uterine (polyps, fibroids, adhesions, thin lining, or an abnormal window of implantation), or immune/thrombotic.

Evaluation may include hysteroscopy, ERA, PGT-A, thrombophilia testing, and immunological workup. Treatment is highly individualized. PGT-A to select euploid embryos and hysteroscopy to correct uterine abnormalities have the strongest evidence. Many other add-on treatments (intralipid infusions, steroids, IVIG) are used but lack robust randomized trial data.