Ovarian Tissue Cryopreservation
Ovarian tissue cryopreservation at a glance
- Ovarian tissue cryopreservation seeks to preserve fertility in a woman undergoing a fertility-toxic treatment, such as chemotherapy, by surgically removing ovarian tissue and freezing it for transplantation into the woman’s body after treatment.
- Ovarian tissue cryopreservation removes a piece of the ovary from the body and cryopreserves it, which involves freezing and storing it to halt biological activity.
- Ovarian tissue cryopreservation is an experimental treatment according to the American Society for Reproductive Medicine.
- It is the only fertility preservation option for pre-pubescent girls needing fertility-damaging medical treatments, as they have not yet ovulated and may not be able to after their treatment.
What is ovarian tissue cryopreservation?
Ovarian tissue cryopreservation is a surgical method of fertility preservation primarily used before a fertility-damaging treatment. This most often occurs when aggressive chemotherapy or radiotherapy treatment of malignant cancer is immediately necessary. In these instances, the woman will not have time to undergo the preferred method of fertility preservation involving ovulation stimulation, egg retrieval and egg or embryo cryopreservation before her treatment.
Ovarian tissue cryopreservation is also an option for women who are to undergo stem cell transplantation for such diseases as sickle cell anemia. Women who have autoimmune diseases resistant to therapy and those with genetic mutations posing high risk for ovarian failure may also undergo ovarian tissue cryopreservation. It is also an option for prepubescent girls requiring treatment that could render them infertile, because they have not ovulated eggs that could be frozen before treatment and may not be able to ovulate after treatment.
In ovarian tissue cryopreservation part of an ovary is removed from the body prior to treatment. Retrieving a small amount of ovarian cortical tissue, where most eggs are located, enables the cryopreservation of many eggs. The ovarian tissue is most often obtained through minimally invasive laparoscopy. The tissue is frozen to sub-zero temperatures, either through slow-cooling or rapid vitrification, and stored, preserving the woman’s chance of reproduction later.
Whole ovary cryopreservation is an option. However, no pregnancies have been reported from the transplantation of a whole ovary that has been cryopreserved, so the procedure isn’t used often.
Cryopreservation halts all biological activity, so the tissue will neither grow nor die while in the frozen state. The actual amount of time that tissues can stay in cryopreservation is unknown, but it is considered to be indefinite.
When the woman’s medical treatment is over, the ovarian tissue is thawed and transplanted into a specific area of her ovary. After transplantation, ovarian function may be restored. Normal ovulation has been reported within 4-9 months. If the ovary continues to release eggs, the patient may be able to achieve pregnancy without any further fertility treatments, such as in vitro fertilization (IVF).
Risks of ovarian tissue cryopreservation
A major risk of this procedure is the possibility of reintroducing malignant cancer cells into the body. Blood-borne pathogens, such as leukemia, tend to have a higher risk of reinfection, but some other cancers can also get reintroduced to the body.
Ovarian tissue cryopreservation also carries all of the risks associated with surgery, including the surgery to remove the tissue and the surgery to transplant it back into the woman. These risks include reaction to anesthesia, blood loss, clotting, scarring and infection.