Cryopreservation of Ovarian Cortex Tissue

Ovarian tissue cryopreservation (OTC) is applied as a fertility preservation option for women and girls who are at risk of losing ovarian function due to medical treatments with gonadotoxic side effects, such as chemotherapy or radiotherapy. Especially in prepubertal girls, it is the only option for fertility preservation. Two modes of OTC are practiced: Vitrification and slow freezing. The aim of OTC is the preservation of follicles. Reimplantation of the ovarian tissue provides the patient with a follicle pool, in order to increase the chances of becoming pregnant by serving oocytes and the ovarian hormonal functions. Vitrification of ovarian tissue is a modern cryopreservation technique that rapidly cryopreserves tissue to prevent ice crystal formation, which can damage cells. It is increasingly studied and applied as an alternative to slow freezing. Current meta-analyses indicate that both techniques appear to provide comparable outcomes. Vitrification provides several advantages, including time and cost reduction due to shorter protocols and the omission of slow freezing equipment. Here, we provide a detailed protocol for ovarian tissue vitrification.