冷凍卵子 vs  新鮮卵子  懷孕率類似

冷凍卵子受損率約10-20%

卵子捐贈者之年齡是影響冷凍結果之關鍵

https://academic.oup.com/biolreprod/article/106/2/316/6485190?login=false

• Though oocytes can be cryopreserved without ice crystal formation through vitrification, it is still not clear whether the process of vitrification causes any negative impact (temperature change/chilling effect, osmotic stress, cryoprotectant toxicity, and/or phase transitions) on oocyte quality that translate to diminished embryo developmental potential or subsequent clinical outcomes. 
•  Currently, the most used human oocyte vitrification method is using the combination of EG and DMSO in order to achieve the lowest concentrations required from each individual CPA [8, 10, 12, 14, 25].
• The authors concluded that outcomes obtained with vitrified oocytes are as good as those with fresh oocytes [15].
• most of the oocyte vitrification studies lead us to conclude that the developmental capability of embryos obtained from vitrified oocytes is not affected by the vitrification procedure, as fertilization, embryo cleavage, embryo quality, and clinical results were similar to those achieved with fresh oocytes. 
• a portion of the vitrified oocytes did not survive the vitrification and warming process (~20%), 
• The results show that fertilization and early embryo development (defined by day 3 good-quality embryo rates and blastocyst formation rates) were not statistically significantly different in the vitrified oocytes compared with the fresh sibling oocytes. 
• These results strongly imply that the potential negative impact of vitrification on oocytes can be minimized. 
• The oocyte spindle has shown rapid depolymerization when exposed to sub-physiological temperatures [86, 88]
• the time interval between each cell division was not changed, indicating that DNA replication was not disrupted in the embryos coming from vitrified oocytes. 
• Despite this statistically significant delay the time to blastulation, the duration of the cell cycle was still consistent with fresh counterparts [127, 128]
• It remains unknown whether the process of vitrification causes subtle damage