Vitrfication and Slow Freezing for Cryopreservation of Germinal Vesicle-Stage Human Oocytes: A Bayesian Meta-Analysis.

ABSTRACT

BACKGROUND: T he most commonly used methods for the cryopreservation of oocytes and embryos are vitrification and slow freezing. OBJECTIVE: The aim of this study was to to investigate whether there are differences in survival, in vitro maturation (IVM), and fertilization rates between cryopreserved immature oocytes, especially germinal vesicle (GV)-stage human oocytes, following vitrification and slow freezing. MATERIALS AND METHODS: A literature search was performed using the MEDLINE, Cochrane Central Register of Controlled Trials, and Embase databases. A total of three studies were included in the Bayesian meta-analysis. RESULTS: There was no difference in survival rates between vitrification and slow freezing. Additionally, there was no difference in IVM rates and fertilization rates between vitrification and slow freezing. CONCLUSION: The superiority of vitrification over slow freezing for cryopreservation of GV-stage human oocytes remains unclear. Additional studies on cytoarchitecture and modification of the cryopreservation protocol are essential to achieve strong conclusions.