Vitrification of Human Oocytes and Embryos of Different Development Stages

Abstract

Cryopreservation of oocytes and embryos leads to increased cumulative pregnancy rates, enables the recovery of the cost of treatment for Assisted Reproductive Technology (ART), minimizes risks of ovarian hyper stimulation syndrome (OHSS) through reducing number of stimulated cycles, reduces the risks of multiple pregnancy, allows patients undergoing chemotherapy and radiotherapy to preserve their fertility. In addition it also offers hope to those with genetic diseases such as Turner Syndrome and premature ovarian failure, or both. With the high viability rates now obtained following cryopreservation by vitrification of oocytes and embryos it is no longer a concern that compliance with regulation of certain countries that requires selection of limited number of oocytes for fertilization or the transfer of single embryos will compromise the patients' chances of achieving pregnancy. Considerable effort is now focused on optimising the vitrification technique of cryopreservation worldwide. It is recommended vitrification is used instead of slow freezing as the latter is costly necessitating the purchase of programmable freezers, tedious and time consuming.