Survival and post-warming in vitro competence of human oocytes after high security closed system vitrification

Abstract

Purpose: To compare two vitrification methods and two warming methods for human oocyte vitrification using a high security closed device in terms of survival, fertilization and embryo development. Methods: For vitrification, oocytes were (1) immediately placed in equilibration solution or (2) they were gradually exposed to the cryoprotectants. For warming, oocytes were placed (1) in a 25 μl preheated (37 °C) thawing solution droplet that was put at room temperature for 1 min once the oocytes were inside or (2) in a 150 μl droplet for 1 minute at 37 °C. Results: Survival and preimplantation development were significantly lower when warming was performed in a small preheated droplet. There was no significant difference in survival and embryo development between the gradual or direct exposure to cryoprotectants. Conclusions: Using this high security closed vitrification device a 90 % survival rate can be achieved when the oocytes are immediately warmed in a large volume at 37 °C. © 2013 Springer Science+Business Media New York.