Menstrual flow

Menstrual flow

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: November 22, 2021

Author: Healthwise Staff
Medical Review:
Sarah Marshall MD - Family Medicine
Martin J. Gabica MD - Family Medicine
Kathleen Romito MD - Family Medicine
Rebecca Sue Uranga MD - Obstetrics and Gynecology
JoLynn Montgomery PA - Family Medicine