Embryo Cryopreservation and
Frozen Embryo Transfers (FET)
Sometimes couples have extra embryos available after an IVF procedure. In such cases, couples may decide on cryopreservation (freezing) to store embryos a future IVF cycle.
Frozen embryos may be stored for 5 years or more. To use frozen embryos, they must be thawed and an embryologist will examine them to see if they survived freezing. Typically, 10-20% of the embryos do not survive the freezing and thawing process.
Most couples with surplus embryos from a prior IVF cycle, who desire more children, often plan for the embryo transfer within 2 - 3 years of their last cycle. It's been suggested by fertility specialists that embryos be used within 5 years of storage for ensure the best chance of success.
Pregnancy rates with frozen embryos have been shown to be similar to non-frozen embryos of equal quality. However, sometimes the best quality embryos had been transferred to the uterus in the IVF cycle, so the surplus frozen/thawed embryos may be associated with a somewhat lower pregnancy rate.
A frozen embryo transfer (FET) cycle is easier and less costly than a regular embryo transfer. The woman does not need to take follicle stimulating medications, and the cycle is less invasive since there is no egg retrieval involved. In addition, the cost of a frozen embryo transfer cycle is much less than the cost of a regular IVF cycle.