Recurrent implantation failure (RIF) is the failure to achieve a clinical pregnancy following the transfer of at least four good-quality embryos in a minimum of three fresh or frozen cycles in a woman of age below 40 years.

The Recurrent implantation failure can be caused by several different factors including uterine pathologies (fibroids, endometrial polyps, congenital anomalies, and intrauterine adhesions.), reproductive tract microbiome, thrombophilia, maternal immune system (uterine natural killer cells), endometrial receptivity, male factors, and genetics of the embryo.

There are multiple risk factors for recurrent implantation failure including advanced maternal age, smoking status of both parents, elevated body mass index, and stress levels.

Careful clinical evaluation prior to assisted reproduction can uncover many treatable causes.