Periods happen because of a natural monthly cycle in the female body preparing for possible pregnancy. Every month, hormones stimulate the ovaries to release an egg and the lining of the uterus to thicken to support a fertilized egg. If pregnancy does not occur, hormone levels drop, causing the thickened lining of the uterus to break down and shed, resulting in bleeding known as a period.

How Periods Work

• The menstrual cycle lasts about 28 days on average.
• Hormones from the brain and ovaries coordinate the thickening of the uterus lining and the release of an egg (ovulation).
• If the egg is not fertilized, hormone levels fall, leading to the shedding of the lining of the uterus.
• The bleeding during a period is the shedding lining leaving the body through the vagina.

Purpose of Periods

• Periods are a sign that pregnancy has not occurred.
• The cycle then begins again with the body preparing for another potential pregnancy.

Additional Notes

• The amount of blood lost during a period is typically about 2 to 3 tablespoons.
• Periods usually start in puberty and continue until menopause.
• The menstrual cycle can vary in length and symptoms between individuals.

This monthly shedding is a normal and healthy part of reproductive biology in females with a uterus.