Cryopreservation
Cryopreservation is a method of preserving sperm, oocytes, or embryos for future use. The lab will freeze sperm by freezing it to sub-zero temperatures, such as -196 degrees Celsius, during the procedure. In other terms, cryopreservation is a method of freezing and storing sperm, eggs, or "leftover" embryos from an in vitro fertilization cycle in infertility treatments. Slow freezing and vitrification are the two ways of freezing currently used in IVF labs.
Cryopreservation involves freezing sperm, eggs, and embryos at a sub-zero temperature in order to preserve them for use in the future. There are three main methods of cryopreservation:
- Cryopreservation of sperm
- Cryopreservation of eggs
- Cryopreservation of embryos
Sperm is frozen for a variety of reasons: a) to develop a sperm bank; b) to donate stored sperm; c) to use it during treatment if the male partner is unable to ejaculate on the stipulated day; d) prior to vasectomy; e) prior to cancer treatment that may affect fertility; f) retrieved sperm from epididymis (PESA) or testes (TESA).
The storage duration for sperm frozen for the donor's imminent treatment is usually one year. The term pre-chemotherapy storage is usually 10 years, however, it might be extended in specific instances.
Women who are set to receive medical treatment for conditions such as cancer or other illnesses that may impact their ability to produce eggs in the future may benefit from egg cryopreservation. This method can also be used for women who are career-driven and do not wish to start a family too soon.
The usual freezing procedure is used to freeze eggs within a few hours following collection. When a woman is ready to get pregnant, the frozen eggs are thawed, fertilized with her husband's sperm, and the embryo is put in the uterus.