Chapter 20 - Vitrification of Oocytes for IVF

Summary

Oocyte cryopreservation is of utmost importance in many aspects of assisted reproductive techniques (ART), offering several valid solutions to clinic, logistic and social problems. Unfortunately, until recently, oocyte cryopreservation has been largely neglected, mostly due to the remarkable technical difficulties related to cell special structure and sensitivity. Since the first human birth reported from a frozen egg, considerable efforts have been made to improve a defective protocol: cryopreservation systems evolved considerably during the years, shifting from conventional ’slow-freezing’ to more effective ’vitrification’ methods. Notably, the advent of vitrification dramatically increased the cryopreservation efficiency in terms of survival and, more importantly, pregnancy rates, such that it is today considered the method of choice to preserve both gametes and embryos, finally freed of the heavy label ’experimental’.