“Through its cannibalistic actions, the trophoblast performs the dual functions of accomplishing implantation as it carves out a hole in the endometrium for the blastocyst and making metabolic fuel and raw materials available for the developing embryo as the advancing trophoblastic projections break down the nutrient-rich endometrial tissue. The plasma membranes of the advancing trophoblastic cells degenerate, forming a multinucleated syncytium that will eventually become the fetal portion of the placenta.

“Stimulated by the invading trophoblast, the endometrial tissue at the contact site undergoes dramatic changes that enhance its ability to support the implanting embryo, such as increased vascularization and enhanced nutrient storage.”