The Frozen Embryo Transfer (FET) — in German Kryotransfer — is the embryo transfer of a previously cryopreserved and thawed embryo.
In Europe already 368,000 cycles in 2021 (ESHRE Focus on Reproduction); frequently carried out as a single-embryo transfer. It presupposes that the embryo was previously cryopreserved — and thus FET structurally continues the production of surplus embryos.
Ontological Classification
- is subclass of: embryo transfer
- presupposes: cryopreservation
Personal-Ontological Assessment
The embryo introduced through FET is, from fertilization onward, a complete human person with full ontological dignity. The cryopreservation was a state, not a change of essence.
Sources: Research status 25 April 2026.
Further sources:
- ESHRE EIM Consortium (2024): ART in Europe, 2021: preliminary results. Human Reproduction 39, Supplement 1, deae108.136 (368,464 FET cycles in 2021).
- Roque, M. et al. (2019): Fresh versus elective frozen embryo transfer in IVF/ICSI cycles: a systematic review and meta-analysis of reproductive outcomes. Human Reproduction Update 25(1): 2–14.
- Maheshwari, A. et al. (2022): Elective freezing of embryos versus fresh embryo transfer in IVF: a multicentre randomised controlled trial in the UK (E-Freeze). Human Reproduction 37(3): 476–487.
- Wennerholm, U. B. & Bergh, C. (2020): Perinatal outcomes of children born after frozen-thawed embryo transfer: a Nordic cohort study. Human Reproduction Update 26(2): 159–176.