BLASTOCYST
What Is A Blastocyst?
During conception inside a woman's body, the egg is fertilized by sperm in the fallopian tube and an embryo is formed. Eggs are retrieved from a woman's ovaries, fertilized with sperm, and an embryo is created. The embryo divides and multiplies its cells over 5 to 6 days to become a blastocyst. Embryos that survive to this stage of development have a high implantation potential once transferred into the uterine cavity.
Grade 1:
The embryo has the appropriate cell number for stage of development (eg., on day three, embryos should have 8 cells, also known as blastomeres) and the cells are even in their size and shape. The embryos should have little or no fragmentation (small amounts of extracellular debris) between cells.
Grade 2:
The embryo has the correct development of cell numbers (6-8 cells on day three), with a small amount of fragmentation (20% fragmentation), or slight uneveness of blastomere sizes. grade 3 the embryo contains blastomeres that are uneven in size and has more than 30% fragmentation. embryos developing slowly will also receive a grade of 2 or 3 even if they are normal otherwise. grade 4 the embryo contains very few, if any, viable appearing cells and has a high percent fragmentation (over 50%).