What is a Frozen Embryo Transfer?
It is not uncommon for couples to have more embryos than they need after an in vitro fertilization (IVF) cycle. Frozen embryo transfer (FET) is used to preserve these extra embryos for future use. During the embryo transfer process, which normally lasts about 3-4 weeks, the uterus is prepared with both estrogen and progesterone hormones to make the uterus receptive. Cryopreserved embryos are then thawed and transferred back into the uterus. Approximately 80% of embryos survive the freeze-thaw process.
Embryos are dehydrated prior to freezing in an effort to minimize the formation of ice crystals in the embryo, which can cause intracellular damage. Embryo cryopreservation techniques and capabilities have become an increasingly important therapeutic strategy in assisted reproduction. So much so, that statistics show 20% of all offspring born worldwide from IVF cycles are from embryo cryopreservation and frozen embryo transfer procedures.
Frozen embryo transfer can be done whenever you have frozen embryos and wish to use them. FET is most often used after an unsuccessful stimulated IVF cycle, in which you have obtained frozen embryos.
Are there benefits of a frozen embryo transfer (FET) over a fresh (stimulated) cycle?
A FET a good and practical choice over a fresh stimulated cycle if a patient has frozen embryos to use. Some of the advantages include lower cost, less complex treatment, less medication, and generally similar success rates.