When does the implantation occur?

Embryonic implantation is the process whereby the embryo attaches to the endometrium to receive oxygen and nutrients from the mother through the blood, and can thus continue its development. In order to implant, it is essential that the embryo is in the blastocyst stage and the endometrial blood vessels are torn to form new ones, which will allow the exchange through the mother’s blood. Tearing of the small endometrial vessels causes the well-known implantation staining.