Successful live birth from vitrified oocytes after 5 years of cryopreservation

Abstract

To report a birth of a healthy boy after long-term cryopreservation of oocytes by vitrification. Clinical application. IVF Center. A 17 year-old female with secondary pulmonary hypertension caused by transposition of great vessels visited our center in 2002, and she wished oocytes cryopreservation to avoid possible sterility after the following category X medication treatment. Vitrified oocytes on Electron Microscope (EM) grids were warmed after 5 years of storage. Surviving MII oocytes were microinjected for fertilization and two embryos were transferred into a gestational carrier day 5 after microinjection. Survival, fertilization, cleavage, clinical pregnancy and delivery. Eleven out of fourteen oocytes (78.6%) survived warming. Eight Metaphase II (MII) oocytes and 3 in vitro matured oocytes were microinjected; all 11 oocytes (100%) fertilized and 2 embryos were transferred on day 5. A healthy baby boy weighing 3,600 g was delivered at 38 weeks of gestation. Live-birth rates per warmed oocyte and per injected oocyte were 7.1% and 9.1% respectively. Cryopreservation after vitrification with EM grids maintained the developmental competence of oocytes after long-term storage and resulted in a successful live birth.