Chapter 8 Human Oocytes Slow-Rate Freezing: Methodology.
Cryopreservation of human oocytes is an important technique for the treatment of human infertility, as it deals successfully with legal, ethical, and moral issues related to embryo cryopreservation (Coticchio et al., Human Fertil (Camb) 4:152-157, 2001; Tucker et al., Eur J Obstet Gynecol Reprod Biol 113: 524-527, 2004) and maintains reproductive potential in women with diseases or conditions that may compromise reproductive capacity. Here, we describe an oocyte cryopreservation technique involving slow freezing-rapid thawing with differential sucrose concentration (0.2 M in the freezing stage-0.3 M in thawing stage) (Bianchi et al., Reprod Biomed Online. 14:64-71, 2007), describing the technique in detail, from the preparation of the solutions through to the performance of the technique and, finally, to a number of helpful hints for optimum results.