Embryologist's tips: "What determines the ability of an embryo to be implanted into the uterine cavity?"

Embryologist’s tips: Embryo quality can be rated combining three indicators – morphology, kinetics and genetics. The ability of an embryo to be implanted by 25% depends on its morphology, 25% on kinetics and 50% on genetics.
We’ll talk about embryo morphology today.
Embryo morphology is visual embryo assessment by cell count and size and fragmentation amount in an embryo.
Blastocyst development and stage status (Gardner et al. 1999):

BC1 – Blastocoel cavity less than half the volume of the embryo
BC2 – Blastocoel cavity more than half the volume of the embryo
BC3 – Full blastocyst, cavity completely filling the embryo
BC4 – Expanded blastocyst, cavity larger than the embryo, with thinning of the shell
BC5 – Hatching out of the shell
BC6 – Hatched out of the shell
From the second blastocyst development stage (BC2), it is possible to rank inner cell mass and trophectoderm (Gardner et al. 1999):
Inner cell mass quality:

A – Many cells, tightly packed;
B – Several cells, loosely grouped;
C – Very few cells.
Trophectoderm quality:

A – Many cells, forming cohesive layer;
B – Few cells, forming loose epithelium;
C – Very few large cells.