Embryo freezing is the process where embryos created in the laboratory are frozen using the latest Vitrification technique (also known as fast freezing) and stored safely for future use.
Embryos can be frozen as a way of preserving fertility or as part of IVF treatment, where any embryos of good quality not transferred are frozen. Any embryos frozen can be thawed and transferred into the womb during a simple procedure called a Frozen Embryo Transfer.
Embryos can be frozen on the 1st, 2nd, 3rd or 5th day after oocyte retrieval. Embryologists assess them based on international criteria and estimate which embryos are viable and can yield a pregnancy. These embryos are suitable for cryopreservation, which we recommend, as it increases total pregnancy achievement rates. At our lab, only good quality embryos are frozen, because lower quality embryos usually don’t survive thawing.
If embryos are cultured until the blastocyst stage, usually there are no redundant blastocysts to be cryopreserved (the best embryos are selected via blastocyst culture). Embryos can remain frozen for up to 20 years, under the appropriate conditions of cryopreservation. Survival rates after freezing/ thawing reach 98%. In any case, the couple discusses with the doctor on “whether” and “when” the embryos will be cryopreserved and decision is made jointly.
The method of cryopreservation actually increases pregnancy achievement rates without repeating stimulation, because if the cycle with the “fresh” embryos doesn’t succeed, there are many chances for the cycle with the frozen embryos to have a positive outcome. Besides, many clinical researches show that pregnancy achievement rates don’t vary depending on whether fresh or frozen embryos are transferred.
Women who are not yet ready for a child may choose to create embryos with their partner’s or donor sperm and freeze them for a pregnancy in the future.
