To be suitable for freezing, embryos must be growing at the expected rate and have few fragments between the cells of the embryos. If only one embryo is frozen from the original cycle, it is recommended that further IVF cycles are undertaken in order to have sufficient embryos for subsequent thawing and transfer.
If donor gametes are involved, embryos from different donors cannot be transferred together. It is important to be aware that approximately 75% of frozen embryos survive thawing in a condition which is suitable for transfer. This can be a very disappointing stage if you have had preparation for a frozen transfer cycle. The staff will be available to discuss this and support you and endeavor to provide the next step of your infertility care.
Long-term storage of frozen embryos is not recommended as a routine. The current Guidelines recommend that embryos not be stored for longer than five years other than in specific circumstances.