Stages of embryo development
During the follicle puncture, the follicular fluid goes to the embryologists’ table, where mature egg cells are selected and prepared for the upcoming fertilization with partner’s or donor’s sperm.
The fertilization quality can be evaluated in 16-18 hours.
On the second day, an embryo starts dividing in 2 parts - blastomeres. By the 3rd day, the number of blastomeres is increased to 8. It is the 3rd day when the embryos with genetic pathology can stop growing.
By the 4th day, the number of cells contained in an embryo increases to 10-16. This stage of embryo development is called morula.
On days 5-6, a morula becomes a blastocyst, which consists of two kinds of cells: trophoblasts and inner cell mass (which all tissues and organs of the baby will originate from). It is this stage of embryo development when trophectoderm biopsy (the collection of several cells from the external cell mass) is carried out either for genetic testing or for an embryo transfer.