|The IVF (in vitro fertilization) and ICSI (intracytoplasmic sperm injection) treatments often produce more embryos than are needed for a single embryo transfer. In these cases, it is possible to freeze the spare, good quality embryos for later use. They can be kept for many years in liquid nitrogen (-196 °C). Approximately 70% of the frozen embryos are transferrable into the uterus after thawing. |
The transfer of frozen embryos is normally done in the natural cycle (a few days after ovulation) or the hormonal cycle, where the endometrium of the uterus is matured with light hormonal medication.
The frozen embryos belong to the couple together, and their use is decided upon by the couple collectively. The agreement regarding the maintenance of the embryos can be renewed yearly; there is a yearly charge for renewing this agreement.