Human Oocyte Slow Freezing

Cryopreservation of human oocytes is a valuable technique for the treatment of infertility, resolving legal, ethical, and moral issues related to embryo cryopreservation (Coticchio G et al., Human Fertil 4:152–157, 2001; Tucker M et al., Eur J Obstet Gynecol Reprod Biol 113:524–527, 2004). It also preserves the female reproductive potential endangered by pathologies or other conditions. Here, we describe an oocyte cryopreservation technique based on slow freezing-rapid thawing with differential sucrose concentration (0.2 M in the freezing stage, 0.3 M in thawing stage) (Bianchi V et al., Reprod Biomed Online 14:64–71, 2007), describing the technique in detail, methods, management, organization, and safety of oocyte cryopreservation.