Orthotopic and heterotopic ovarian tissue transplantation.

Although still experimental, cryopreservation and transplantation techniques for ovarian tissue have been well described, and a number of successful human pregnancies have occurred. Ovarian cryopreservation is the only fertility preservation procedure that can be offered to prepubertal children, and when cytotoxic treatment is urgent. There are two main approaches for autotransplantation of human ovarian tissue. In the heterotopic transplantation, cortical fragments can be grafted subcutaneously at various sites whereas in orthotopic transplantation cortical pieces are transplanted into its original location. Both approaches have their own advantages and disadvantages. While natural pregnancy can occur in orthotopic transplantation, heterotopic transplantation may be indicated if the pelvis is not suitable for transplantation due to previous radiation or severe scar formation. Furthermore, tissue monitoring may be easier in the heterotopic site. In this article, we reviewed the indications, limitations, risks and transplantation techniques for ovarian tissue.