Cryopreservation and Delayed Embryo Transfer-assisted Reproductive Technology Registry and Reporting Implications

Clinics performing assisted reproductive technology (ART) procedures have collected data via registry and publicly reported pregnancy outcomes for more than 25 years. During this time, the practice of ART has changed considerably with frozen embryo transfer (FET) procedures contributing an increasing proportion of live births. Cycles initiated with the intent of embryo banking for the purpose of fertility preservation have been excluded from these public reports, because pregnancy outcomes are not immediately available. An unintended consequence of the common sense handling of fertility preservation has been that cycles performed with intentional short-term cryopreservation of all embryos for other indications have also been excluded from the report. Over the last few years, cryopreservation with short-term delayed transfer increasingly has been performed for reasons other than fertility preservation. The pregnancy outcomes of these cycles are expected within a reasonable time frame and should be transparently reported. The Society for Assisted Reproductive Technology has collaborated with the Centers for Disease Control and Prevention to "recapture" these cycles for the public reports. This recapture is done by linking the FET cycles to the stimulation cycles from which the embryos were derived and by changing the labels of the outcome success metrics. Stimulations using ART, initiated for the purpose of transferring embryos within 1 year will be included in the report despite any prospective intent to freeze all eggs or embryos. A positive outcome will be reported when a live birth results from the first embryo transfer following stimulation ("primary transfer"). Linkage of ovarian stimulation and egg-retrieval procedures to FET will also allow development of other success metrics to further benefit fertility patients.