Embryo Freezing

Surplus embryos that are not transferred to the patient's uterus can be frozen ("cryopreserved") for future use by the couple. The cryopreservation of embryos is carried out either on the third day after egg retrieval when the embryo is between 6 and 8 cells in size or on the fifth or sixth day after egg retrieval (the "blastocyst" stage). Embryos that have potential to become successful pregnancies in the future are cryopreserved.