In-vitro maturation of oocytes from ovarian tissue expands fertility preservation options

Abstract

Ovarian tissue cryopreservation is a fertility preservation option for pre-menarchal girls and women who cannot delay their cancer treatment. While oocyte and embryo cryopreservation have become standard procedures in many in vitro fertilization laboratories, ovarian tissue cryopreservation remains experimental. We report our unique experience of isolating, maturing, fertilizing and cryopreserving oocytes directly from ovarian tissue in cryopreservation cases. Case series. Ovarian tissue was harvested from consented patients undergoing ovarian tissue cryopreservation. Antral follicles were aspirated and cryopreserved according to the protocol of the National Physicians Cooperative of the Oncofertility Consortium. The follicular aspirates, medullary tissue, and holding media in which the ovaries were processed were examined for oocytes. Immature oocytes were placed in standard media or in maturation media supplemented with menotropins. Maturation was assessed at 24-48 hours post-isolation. Oocytes were cryopreserved or fertilized with intracytoplasmic sperm injection. Embryos were cryopreserved 2 days post-fertilization. From 2008-2011, 8 patients, ranging in age from 17 months to 42 years underwent ovarian tissue cryopreservation at Women & Infants Hospital. Eighteen oocytes were recovered from 5 patients. Ten oocytes were cultured in standard media for 24 hours and did not mature. The remaining 8 oocytes were cultured in supplement maturation media, resulting in 1 M1 oocyte and 5 M2 oocytes (62.5% maturation). In one case, 3 M2 oocytes were fertilized resulting in 3 embryos. Oocytes isolated from ovarian tissue can be matured with in vitro maturation media, fertilized and cryopreserved. This technique offers an additional form of fertility preservation for girls and women choosing ovarian tissue cryopreservation.