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A Complete Guide to Day-5 Embryo Grading
Hey, my name is Sean, but I also go by Embryoman, and I'm here today to talk to you about blastocyst or day 5 grading. First, let's look at some key parts of the blastocyst. The zona is the shell that surrounds the embryo, the inner cell mass, or ICM, goes on to form the fetus, and the trifecta derma goes on to form the placenta. When it comes to the actual embryo grade, the number refers to the expansion, and goes from 1 to 6, the first letter refers to the quality of the ICM, which can be A, B, or C, and the second letter refers to the quality of the trifecta derma. As the expansion number increases, the embryo's size generally increases too. A blastocyst with an expansion of 3 is generally smaller than one with expansion 4. ICM and trifecta derma quality depend on the number of cells present. An A-grade ICM has more cells than a C-grade ICM, and an A-grade trifecta derma has more cells than a C-grade trifecta derma. Embryo grading is used to rank embryos for transfer, as embryos of higher quality tend to have a better chance than embryos of lower quality.