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 the first day of bleeding. In the middle of the cycle, ovulation occurs. This is when an egg is released and begins its journey from the ovary to the uterus.

Front view cross section of uterus, vagina, fallopian tube, ovary, and egg. Arrow shows path of egg from ovary to lining of uterus.

An egg is released

During each cycle, 1 egg grows and is released from an ovary. It finds its way to the fallopian tube. (If the egg and a man’s sperm meet, a woman may become pregnant.)

The egg travels through a tube

The egg moves through the fallopian tube toward the uterus. 

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.)