Question

What is implantation ? When does this process begin?

Answer 1

On the sixth day following fertilisation, the blastocyst gets attached to the wall of uterus in such a way that the side of inner cell mass is positioned against the endometrium. The trophoblast cells produce some enzymes that help the embryo to 'eat its way' into the thick endometrium. This begins the process of implantation. By the seventh to tenth day following implantation, the blastocyst is completely embedded or implanted in the endometrium.