In-vitro maturation of human oocytes: before or after vitrification?

Research Laboratory on Human Reproduction, Medicine Faculty, Université Libre de Bruxelles, Belgium, Campus Erasme, Brussels, Belgium.
Journal of Assisted Reproduction and Genetics (Impact Factor: 1.82). 04/2012; 29(6):507-12. DOI: 10.1007/s10815-012-9751-9
Source: PubMed

ABSTRACT This study aims to determine if in-vitro maturation (IVM) of human immature oocytes should be performed before or after vitrification.
A total of 184 immature oocytes were randomly divided into two different groups: 100 were vitrified at metaphase II (MII) stage 24 h-48 h after IVM (group 1) and 84 were immediately vitrified at germinal vesicle (GV) or metaphase I (MI) stages and in vitro matured after warming (group 2).
Survival rate after warming was similar in both groups (86.9% versus 84.5%). However, oocyte maturation rate per collected oocyte was significantly higher for oocytes matured before vitrification (group 1, 46%) than for oocytes vitrified before IVM (group 2, 23.8%) (p < 0.01). Consequently, the number of MII oocytes inseminated per oocyte collected was significantly higher for group 1 (40%) than for group 2 (23.8%) (p < 0.05).
IVM procedure is more efficient when it is performed before oocyte vitrification.

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