Placenta percreta
A placenta that invades the uterine wall.
In placenta percreta, the vascular processes of the chorion (the chorionic villi), a fetal membrane that enters into the formation of the placenta, may invade the full thickness of the myometrium.
This can cause an incomplete rupture of the uterus.
The chorionic villi can go right on through both the myometrium and the outside covering of the uterus (serosa), causing complete and catastrophic rupture of the uterus