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Understanding Periods

Having a period is a normal, healthy part of becoming and being a woman. A period is the result of a cycle that takes place inside a girl’s body. This menstrual cycle makes it possible for women to have babies. The cycle begins with ovulation, when an egg is released and begins its journey.

An Egg Is Released

  • During each cycle, one egg grows and is released from an ovary. It finds its way to the fallopian tube.

The Egg Travels Through a Tube

  • The egg moves through the fallopian tube toward the uterus. (If the egg and a man’s sperm meet here, a woman becomes pregnant.)

The Lining Thickens

  • The lining of the uterus grows thicker. This lining is made up of blood, tissue, and fluid. (The lining will nourish a growing baby during pregnancy.)

The Egg and Lining Are Shed

  • About once a month, the egg and the lining of the uterus are shed through the vagina. This is called a period. (A period does not happen during pregnancy.)

 

Publication Source: American Medical Association, American Medical Association Family Medical Guide, 4th ed., 2004, pp 845-853
Publication Source: Boston Women's Health Collective, Our bodies, ourselves, 2005, pp 194
Publication Source: Stenchever MA, Comprehensive gynecology, 5th ed., 2007, pp 105-9
Online Medical Reviewer: McDonald, Thad, MD
Date Last Reviewed: 8/2/2004
Date Last Modified: 7/9/2002