Table 1  Embryo grading according to the cleavage stage embryo scoring system 8 .

Score	Description
Grade 1 and grade 2 embryos were classified as good quality embryos, grade 3 and grade 4 embryos were classified as poor quality embryos; grade 5 embryos were not transferred.
Grade 1	Embryo with 8 – 12 even sized blastomeres and < 5% cytoplasmic fragments
Grade 2	Embryo with 6 – 10 even sized blastomeres, 5 – 20% cytoplasmic fragments
Grade 3	Embryo with uneven blastomeres, ≤ 20% cytoplasmic fragments
Grade 4	Embryo with even or uneven sized blastomeres, 20 – 50% cytoplasmic fragmentation
Grade 5	Embryo with ≤ 4 blastomeres of any size, > 50% or complete fragmentation