An embryo’s ability to develop could stop for a variety of causes. The embryo might have slowed growth or decreased metabolic activity, which would cause it to degenerate. During certain phases of development, embryos can also stop developing. For numerous causes, some of which are covered below, they may not develop to the blastocyst stage.
An embryonic cell typically divides into two cells and evenly distributes its chromosomes. But occasionally, a cell within an embryo divides into three cells. Direct Uneven Cleavage (DUC) is the term for this. Embryo arrest is more likely to happen when DUC takes place in the first cell division.
The degree to which the cells are impacted will also determine the likelihood of embryo arrest. An embryo may occasionally divide quickly, going from one cell to two and then three and this rapid division might be challenging to distinguish from DUC. In these conditions, the embryo that divides quickly is more likely to develop into a blastocyst.
Another mistake in cell division can take place if the cell doesn’t divide but the nucleus—which houses your chromosomes and DNA—keeps replicating. This may result in the presence of many whole sets of chromosomes within a single cell. The embryo will stop growing if this happens in numerous cells, but if it only happens in a small number of cells, the embryo still has a chance of developing into a blastocyst.