Vitrification of mouse two‐cell and blastocyst stage embryos in simplified closed system using either a hemi‐straw or a hollow fiber device

Two‐cell stage and blastocyst stage mouse embryos were equilibrated in a medium containing 7.5% ethylene glycol (EG) and 7.5% dimethyl sulfoxide (DMSO) for 8–15 min. Vitrification was performed in a medium containing 0.5 M sucrose and either 15% EG + 15% DMSO, 17.5% EG + 17.5% DMSO, or 20% EG + 20% DMSO for 30 s. They were then placed either on a hemi‐straw (HS) or a hollow fiber vitrification (HFV) device and vitrified by cooled air inside a 0.5‐ml straw. In two‐cell embryos, a 100% survival rate was obtained from all groups except the 20% HS group (P > .05). All vitrified two‐cell groups showed similar rates of blastocyst development to that of fresh control group (P > .05), except 17.5% and 20% HFV groups, which were significantly lower than the other groups (P