Menstruation is the monthly vaginal bleeding a woman experiences as the uterine lining is shed. Every month, an ovary releases an egg that travels down the fallopian tube to the uterus. If the egg is not fertilized, the egg and lining of the uterus are shed, resulting in menstruation. The average menstrual period lasts from 3 to 5 days, although it can vary from person to person and from month to month.

Menstruation typically begins between the ages of 11 and 14. The average menstrual cycle (the time between periods) is 28 days long. However, cycles vary, and can range from 21 to 35 days. In addition to vaginal bleeding, during her period a woman may experience the following:

  • Abdominal pain or cramping
  • Lower-back pain
  • Sore breasts
  • Abdominal bloating
  • Headache
  • Mood swings
  • Fatigue

Using a heating pad or taking a warm bath can soothe menstrual cramps. Taking over-the-counter pain medication is also usually effective.

A regular monthly cycle can be an important indicator of gynecological functions. Heavy bleeding; severe pain or cramping; bleeding between periods; or periods lasting more than 7 days can be signs of a serious health problem, and should be discussed with a physician. Getting a monthly period continues until menopause, which begins, on average, when a woman is 51 years old.