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Freezing of the embryos and transfer of frozen/thawed embryos 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. |
