Now, by activating the ovaries, they initiate a monthly process known as the menstrual cycle. Now what the menstrual cycle is it's a series of events that lasts about 28 days. Now of course, this number can differ from one individual to another. In some women it's slightly longer, in others it's slightly shorter. But the entire point of this menstrual cycle is to ultimately prepare that woman for a possible pregnancy. And more specifically, it's to prepare the lining of the uterus for a possible implantation by a zygote.