Table 1. Embryo classification system.
Grade	Parameters
I	Embryo with blastomeres of equal size, no cytoplasmic fragments and clear, homogeneous cytoplasm.
II	Embryo with blastomeres of equal size and less than 30% of the cells contain cytoplasmic fragments.
III	Embryo with blastomeres of different sizes; no cytoplasmic fragments.
IV	Embryo with blastomeres of equal or unequal size, with 30% to 50% of the cells contain cytoplasmic fragments.
V	Embryo with more than 50% of the cells contain cytoplasmic fragments.