Definition - What does Embryo Splitting mean?
Embryo splitting is the process of splitting a single embryo to produce twins. During this procedure, a blastomere biopsy detaches a few cells from an embryo that has reached the 8-cell stage, ideally on Day 3, that are then removed and analyzed for any genetic abnormalities.
If genetically normal, the blastocyst is then bisected into two groups of multiple cells, each of which is returned to the incubator where it should resume further development. These two groups of cells should then grow as identical siblings.
Embryo splitting may also be known as embryo twinning.
FertilitySmarts explains Embryo Splitting
Although embryo splitting may provide additional embryos to be frozen and preserved for women with poor response to hormonal stimulation, it does not appear to offer much benefit to individuals undergoing IVF.
The drawback of the split embryos is that their growth may arrest after a few cell divisions. This is in contrast to embryos developed through IVF that usually exhibit complete development. This may be due to the fact that the IVF embryos follow a “developmental clock,” which is not usually displayed by the split embryos. This clock is vital to a developing embryo, as it denotes a period during which a normal embryo structure begins to emerge.
As such, contrary to what was previously thought, embryo twinning does not appear to provide benefit for real people and has also not shown to be very effective for research purposes.