If you don't ovulate on birth control then why do you have your period?

Hormones: When you take the last pills in the monthly pack they do not contain the same amount of hormone that the others do and therefore your body responds to it by shedding the endometrium. You are not ovulating, but you are still building up and shedding the endometrium based on the hormones (progesterone and estrogen) changing as dictated by the pills.

Good question!: The pill inhibits ovulation but the hormones in the pills mimic some of the hormonal changes that occur during a normal menstrual cycle causing the build up and then shedding of the uterine lining.