The placenta (also known as afterbirth) is an organ that attaches a fetus to the uterine wall and allows for nutrient uptake. It provides thermo-regulation to the fetus, waste elimination, and gas exchange via the mother's blood supply. The placenta, after attaching itself to the uterine wall is connected the the infant through the umbilical cord. When a child is born the umbilical cord is severed and the placenta is then expelled. If the entire placenta is not expelled it can lead to possibly fatal infection.