And so the uterus has to continue to contract to basically loosen that placental membrane and eventually expel that membrane to the outside environment. So eventually the physicians basically tie up the umbilical cord and then they make the cut. And finally, the uterus, the endometrium or the wall of that uterus, begins to regenerate itself and eventually the menstrual cycle will begin once again. And by the way, the menstrual cycle does not take place during the pregnancy period. And that's because we don't want to actually get rid of the lining of the endometrium because we have a growing embryo and a growing fetus within that endometrium. So we see that the human gestation period can be broken down into three stages.