Some women who go through an IVF procedure will create more embryos than they need. The extra embryos can be cryopreserved (frozen) and used for transfer later. However, sometimes couples decide not to use these extra embryos. These people have the option to have their embryos discarded, donated to research, or donated to another woman to achieve pregnancy.
Embryo donation involves using embryos that were created by couples undergoing fertility treatment. These embryos can be transferred into infertile women to help achieve pregnancy. Those who are good candidates for embryo donation are those who have untreatable infertility
that involves both partners, untreatable infertility in a single woman, and those who have recurrent pregnancy loss thought to be related to embryonic factors and genetic disorders affecting one or both partners.
Frozen embryos could also be produced using donated eggs and a partner's sperm to create embryos that are frozen in a staggered IVF donor egg process, which avoids the need for donor/recipient synchronization.
If you are going to receive embryos that have been frozen, the embryos will undergo the thawing process before they are transferred. Embryos can be frozen at several stages of development. Not all embryos will survive the freezing/thawing process. Those that survive are reassessed. If they have damage that may reduce the chance of implantation, the embryos are not considered viable for transfer.
When looking for a fertility clinic, it's a good idea to look at the success rates for each clinic you are considering. The expertise and experience of the lab can make a big difference. Although each facility will have various statistics on success rates, some clinics can have survival rates of up to 95 percent for thawing embryos, with minimal loss of quality to the embryo.
After thawing, the embryos can be transferred into women whose cycle has been synchronized with that of the stage of the frozen embryo. The process for the transfer and follow-up care will be the same as it was for the fresh embryo transfer.
The pregnancy rates following embryo donation will depend on the quality of the embryos that were frozen, the age of the woman who provided the eggs, and the number of embryos transferred.