Does recurrent implantation failure exist? Prevalence and outcomes of five consecutive euploid blastocyst transfers in 123 987 patients.

This article investigates clinical pregnancy and live birth rates in women undergoing up to five consecutive euploid blastocyst transfers after three prior implantation failures, excluding other known factors affecting implantation. An international retrospective study of 105 patients across 25 clinics found that the fourth and fifth euploid blastocyst transfers yielded live birth rates of 40% and 53.3%, respectively, resulting in a cumulative live birth rate of 98.1% after five transfers. These findings suggest that unexplained recurrent implantation failure (RIF) is rare (<2%) when known uterine or embryonic factors are excluded, and that embryo quality remains the primary determinant of implantation success. The study supports continuing embryo transfers with euploid blastocysts as a viable option for patients after multiple failed attempts, while cautioning that further research is needed to assess outcomes beyond five transfers.