Ovarian Tissue Cryopreservation (OTC) Home A-Z Health Information Health Library A-Z Ovarian Tissue Cryopreservation (OTC) Overview Ovarian tissue cryopreservation (OTC) refers to the freezing of the ovarian cortex, i.e., the outer layer of the ovary; this layer is the egg-producing layer of the ovary and often determines the fertility of women. OTC is a useful technique that is most commonly used to preserve fertility and extend childbearing years in women. However, potential applications for OTC beyond fertility preservation include cHRT and cell-/tissue-based hormone replacement therapy for treating cancers in young women and the treatment of other gynaecological conditions, such as premature ovarian insufficiency and polycystic ovary syndrome (PCOS). Why OTC? OTC and transplantation have garnered an increasing amount of attention as successful methods for preserving fertility in young women with primary malignancies; these methods offer them an opportunity to become biological mothers once they have recovered from cancer. Apart from the preservation of the reproductive potential, OTC also enables the endocrine functions of the ovaries to be restored, ultimately protecting the female reproductive cycle by promoting the secretion of natural levels of essential hormones.Given the increasing incidence of the loss of ovarian function resulting from ageing and induced primary ovarian insufficiency (POI), presently, new treatment modalities whereby the surplus of follicles that most women possess since birth can be utilised are urgently needed; this can help women conquer major health issues resulting from the deficiency of ovarian hormones. Procedure for OTC Currently, more than 20,000 girls and women worldwide have been estimated to have undergone OTC. This procedure involves the following steps:First, the ovarian tissues are laparoscopically or surgically removed, followed by freezing of the cortical tissues to yield tissue sections (thickness, approximately 1 mm). Then, the tissues are fragmented mechanically and examined histopathologically to ascertain the presence of malignant cells (and eliminate them) and assess the tissue quality (using the primordial follicle density as an indicator). Finally, the sections are frozen in small fragments.Upon the completion of anti-cancer treatment and recovery, the woman may develop ovarian insufficiency. She is then eligible for ovarian tissue transplantation, which, after tissue thawing, can be performed either orthotopically or heterotopically. This process ensures that the endocrine function is resumed and puberty is initiated.As the cortical tissues primarily contain ovarian follicles at the early stages of follicular development, these tissues require about 3–6 months to regain their full activity and functions, including the sustenance of preovulatory follicle development and the release of fertilisable oocytes. Advantages of OTC Overall, OTC is a useful technique associated with the following advantages:Prior ovarian stimulation is not required. Thus, anti-cancer treatment can be administered immediately.It ensures that the primordial follicles of the ovarian cortex are more resistant to cryoinjury than mature oocytes.A large number of primordial follicles can be cryopreserved; this increases the possibility of maintaining fertility for the entirety of the graft's lifetime and decreases the possibility of multiple IVF attempts being required for achieving pregnancy.Fertility can be preserved for a longer duration than that achieved using embryo and oocyte freezing.OTC offers protection against earlier onset of menopause.