menstrual cycle is the series of changes a woman's body goes through to prepare
for a pregnancy. About once a month, the uterus grows a new lining
(endometrium) to get ready for a fertilized egg. When there is no fertilized
egg to start a pregnancy, the uterus sheds its lining. This is the monthly
menstrual bleeding (also called menstrual period) that women have from their
early teen years until menopause, around age 50.
ByHealthwise Staff Primary Medical ReviewerSarah Marshall, MD - Family Medicine Specialist Medical ReviewerFemi Olatunbosun, MB, FRCSC - Obstetrics and Gynecology