Slow freezing vs vitrification of oocytes: a comprehensive meta-analysis

Abstract

To compare the success of 2 oocyte cryopreservation techniques: Slow Freezing vs. Vitrification. Meta-analysis done after systematic review of literature. All the published articles between 1985 and March 2010 that deal with oocyte freezing by either utilizing a slow freezing or vitrification protocols were studied. Only those studies were included which used mature oocytes, used ICSI for fertilization and eventually had a successful pregnancy outcome. The main outcomes measured were the differences in survival rate, fertilization rate, implantation rate and pregnancy rate in both these protocols. The data was analyzed using the Random effects model in Comprehensive Meta analysis software. 240 articles were scrutinized, 120 were selected on inclusion criterion. Total number of oocytes used in the meta analysis study: Vitrification study: 3424 thawed eggs Slow Freezing: 18020 thawed eggs Table 1.Slow Freezing MethodVitrificationP valueSurvival Rate/Oocyte thawed71.9% [67.44, 75.89] 95% CI 11309/ 1802078.6% [70, 85.18] 95% CI. 2682/ 34240.0000001Fertilization Rate/Oocyte thawed51.2% (2245) [42.2, 60.1] 95% CI.55.96% (1710) [47.4, 67.1] 95% CI.0.0000001Implantation Rate/Oocyte thawed7% (420) [4.3, 11.2] 95% CI7.7% (207) [5.35, 11] 95% CI0.0000001Pregnancy Rate/Oocyte thawed4.2% (324) [3.08, 5.56] 95% CI7.6%(154) [5, 11.4] 95% CI0.7 Open table in a new tab