Answer from: Raúl Olivares, MD
There is a clear correlation between embryo quality and implantation rates. The prettier the embryo is, in terms of morphology, so the embryos have symmetrical cells, with good inner cell mass when we’re talking about blastocyst, the higher the chances for this embryo to implant.
It is, however, not so uncommon that the patients do not get pregnant with the embryos that have been initially transferred. Although they were the best, in terms of assessing them, they eventually get pregnant with the embryos that have been initially frozen because they weren’t as good as the ones transferred. This may sometimes happen in the first cryotransfer or even in the second one.
Though the chances might be slightly worse, on average any embryo graded as B still has some good chances to implant.
Answer from: Harry Karpouzis, MD, MRCOG, DIUE
If we’re talking about blastocysts and grade B embryos, yes, they can get implanted. Even grade C embryos can sometimes get implanted. The grading system of the blastocysts is subjective. The system assesses and grades many different aspects, the cavity size, the inner mass, the trophectoderm which is the part from which the placenta will be formed.
Grade B embryo is not a top-quality embryo which, according to the grading system, is AA, but it’s not a very bad embryo either. Many grade B embryos can be chromosomally normal – if we take a biopsy and do PGT on them, we can discover this. We have seen a lot of pregnancies from grade B embryos. Sometimes when we freeze the embryo, the grading can be one thing, and when this embryo divides more and gets bigger, the grading can change. To sum up, yes, we can have pregnancies with grade B embryos as well.
What does it mean the embryo is grade B? Are grade B embryos good for implantation?
Even though the embryos graded B or C are of worse quality, it doesn’t necessarily mean that such embryos will fail to implant. Does embryo quality affect implantation? Are grade B embryos good?