Of the embryos created during IVF, only a certain number is transferred to the uterus. If the surplus embryos are of good quality, they can be cryopreserved (frozen) for future use. Embryo cryopreservation occurs in liquid nitrogen at -196⁰C in special tanks, and pursuant to Greek Law they may be stored for up to 5 years. Subsequently, if not claimed, they are destroyed.
At Thessaloniki IVF Center, embryos may be frozen at various stages (between the 1st and 6th day following egg retrieval). The couple may utilize the cryopreserved embryos in a new attempt, and the woman will not have to be submitted to ovarian stimulation and egg retrieval, but only to monitoring and embryo transfer.
Freezing is not suitable for all embryos. It requires good quality embryos, in order to maximize the chances of survival after thawing.
The percentage of pregnancies achieved with cryopreserved embryos is now similar to those achieved with fresh. Embryo cryopreservation is an important decision for the couple and may only be undertaken with written consent. Furthermore, the couple must contact the Center once a year to renew the preservation period. To suspend cryopreservation, the written consent of at least one of the partners is required.
The method of embryo cryopreservation is considered safe internationally, since all studies with newborns born subsequent to cryopreservation do not reveal any statistically significant increase in congenital abnormalities.