Vitrification is a technique used to freeze and preserve oocytes (eggs) for future use in fertility treatments. During vitrification, the oocytes are rapidly cooled to a very low temperature, which essentially stops all biological activity and prevents damage to the cells.

Vitrification is a relatively new technique for oocyte freezing, but it has quickly
become the preferred method due to its higher success rates compared to traditional slow freezing methods. Vitrification results in a higher survival rate of the oocytes after thawing, and a higher likelihood of successful fertilization and implantation when the oocytes are used in fertility treatments.