What is embryo freezing and storage?

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.

How long can frozen embryos be stored?

The longest time a human embryo has been stored is almost 40 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 in 2020 a donated embryo that had been frozen for 27 years resulted in the birth of a healthy baby girl.

Are frozen embryos fertilized?

Yes. Embryos are frozen after fertilization and are stored until the desired time of transfer. There are also processes for freezing eggs, or oocytes, prior to fertilization. Fertilization takes place after the eggs are thawed, and then the fertilized egg is ready for transfer.

Are frozen embryo transfers as successful as fresh embryo transfers?

Yes. In fact, a growing number of IVF specialists recommend that their patients consider frozen transfers in place of fresh ones. The success rates for both procedures are very similar.

What is vitrification?

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.