Quality control monitoring of euploid frozen embryo transfers

PURPOSE: The goal of this study is to determine factors associated with fetal heartbeat and live birth rate for euploid frozen embryo transfers. METHODS: This is a retrospective cohort study of IVF patients at a single private practice in Cincinnati, Ohio undergoing single frozen euploid embryo transfer from 1/1/2023 to 7/31/2025. Variables assessed are embryo transfer protocol, genetic testing laboratory, physician who performed the embryo transfer, and embryologist. The main outcomes of interest are fetal heartbeat and live birth rate per single euploid frozen embryo transfer. RESULTS: Fetal heartbeat rate was significantly associated with the frozen embryo transfer protocol (p < 0.01). Modified natural FET protocols without oral medication (such as letrozole) had the highest fetal heartbeat rate of 66% compared to the average fetal heartbeat rate of 52%. Fetal heartbeat rate was also associated with the genetic testing laboratory (p < 0.01) and the day of embryo biopsy (p < 0.01). Fetal heartbeat was not associated with any of the other modifiable measures evaluated including the embryologist performing the biopsy or the physician performing the embryo transfer. CONCLUSION: At our center, the highest ongoing pregnancy rate per euploid embryo is seen with modified natural FET protocols without oral medication (such as letrozole).