Blastocyst culture

The term blastocyst refers to the embryo’s development stage after 5-6 days of culture. It is a hollow sphere and in this stage the embryo consists of 60-200 cells, which form two discrete groups: the trophoblast cells (a peripheral cell mass), which will form the placenta, and the embryoblast (an inner mass of cells), which will form the embryo.

The decision for continued culture at the blastocyst stage depends on the number and quality of embryos on the 3rd culture day, and on the maturity of the endometrium. The main advantage of cultivating embryos at this stage is the option to select the fastest-growing embryos, which statistically give the highest rates of success.