Embryo freezing, or embryo cryopreservation, is the process of preserving embryos by cooling them to deep sub-zero temperatures (-320 degrees fahrenheit). Once the embryos are frozen, they are placed in long-term storage. When the decision is made to use the embryos, they are taken out of storage, thawed, and ready for transfer.
The longest time a human embryo has been stored is around 30 years, but once embryos have been frozen, they can be stored indefinitely. Those who have left embryos in storage for more than a decade typically do not use them; however, frozen embryos have been thawed after nearly 20 years and produced healthy babies.
Yes. Embryos are frozen after fertilization and are stored until the desired time of transfer. There are also processes for freezing eggs (oocytes) prior to fertilization. Fertilization takes place after the eggs are thawed, and then the fertilized egg is ready for transfer.
Yes. In fact, a growing number of IVF specialists recommend that some patients consider frozen transfers in place of fresh ones. The success rates for both procedures are very similar.
Technically, vitrification means the transformation of a substance into glass. Embryo vitrification is the process of freezing embryos into a glass-like state (thus avoiding crystallization). This ultra-rapid process freezes the embryos up to 600 times faster than conventional cryopreservation. Once the embryos are vitrified, they are ready for long-term storage.