High-quality blastocysts are a key factor for the success of IVF. When the embryos are cultured to the blastocyst stage, what does the blastocyst, such as “4AB”, mean? Let’s learn the terminology of blastocysts with the editor! The first number represents the development speed 1 Earlyblastocyst early blastocyst (blastocyst cavity <.1/2 size) 2Earlyblastocyst blastocyst (blastocyst cavity >.1/2 size) 3 Fullblastocyst complete blastocyst 4 Expandedblastocyst . Expanded blastocyst 5 Hatchingblastocyst . Incubating Blastocyst 6Hatchedblastocyst Completely hatched Blastocyst The second letter represents the part of the fetus, that is, the number of grade A cells in the inner cell mass is large and arranged closely. Class B cells are few in number and loosely arranged. The number of grade C cells is small. The third letter represents the part of the placenta that is the trophoblast cell grade. The A-level epithelial cell layer consists of more cell groups, the structure is dense, the B-level epithelial cell layer does not, the multi-structure is loose, and the C-level epithelial cell layer is sparse. The following two letters are only for 3 Blastocyst above grade is effective, because the grade 3 and above can clearly distinguish the area between fetus and placenta! Summary: The first digit in the blastocyst grading represents the developmental speed stage, the second letter represents “connotation”-the quality of the internal cell mass (A is the best), and the third letter represents the “face value”-the quality of the outer trophoblast ( A is the best) For example: 4AB blastocysts are high-quality blastocysts belonging to grade 4 (4-expanded blastocysts; A—the number of cells is large and closely arranged; B—the cells of the epithelial cell layer are not many and the structure is loose), such cysts The success rate of embryo transfer will be relatively high. Do you understand it?