Now we know a zygote is only formed if the woman is sexually active, if fertilization actually takes place. But most of the time fertilization does not take place. So what happens during the menstrual cycle? Well, what happens if fertilization does not occur is the inner lining that is developed during the cycle known as the endometrium begins to break down and it is discharged along with that secondary oicide in a process known as menstruation. And this is categorized by bleeding and by cramping. So this is what women experience on a monthly basis as a result of the fact that no fertilization of their excel actually takes place.