For life-threatening medical emergencies, call 911 without delay. For a mental health crisis, call or text 988 for free and confidential crisis support.
The menstrual cycle is the series of changes the body goes through to prepare for a pregnancy. About once a month, the lining of the uterus (endometrium) thickens. Then an ovary releases an egg. If the egg is fertilized by sperm and attaches to the lining of the uterus (implants), pregnancy begins. If the egg isn't fertilized or a fertilized egg doesn't implant, the lining of the uterus is shed. This is the monthly menstrual bleeding (also called menstrual period) that happens from the early teen years until menopause, around age 50.
Current as of:
April 18, 2023
Author: Healthwise Staff Clinical Review Board All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.
Clinical Review Board All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.
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