Vitrified IVF Morulas.

Vitrified IVF Morulas.
Vitrified morulae after thawing. The embryo at the top is a Grade 4, Code 1 (>85% viable embryo mass). The embryo at the bottom is a Grade 4, Code 2 (50 to 84% viable embryo mass).

Zambrano-Varon J (2012)