When reviewing the following guidelines, take into account how heavy your normal menstrual flow is. Abnormal vaginal bleeding varies depending on what is normal for a particular woman.

• Severe bleeding: You have continuous bleeding that soaks through your usual pad or tampon each hour for 2 or more hours.
• Moderate bleeding: You soak more than 1 pad or tampon in 3 hours.
• Mild bleeding: You soak less than 1 pad or tampon in more than 3 hours.
• Minimal bleeding: You have "spotting" or just a few drops of blood from the vagina.

Vaginal bleeding is considered to be abnormal if it occurs:

• When you are not expecting your menstrual period.
• When your menstrual flow is lighter or heavier than what is normal for you.
• At a time of life when it is not expected, such as:
  • Before age 10.
  • During pregnancy.
  • After menopause.

Many women have bleeding that lasts longer than the usual length of their periods or bleeding between periods. This does not necessarily mean a serious condition is present. Bleeding between periods can have many causes, including:

• Extreme physical or emotional stress.
• Weight loss or weight gain.
• The beginning of menstrual periods (menarche). Periods may be irregular during the first few years of menstruation.
• Perimenopause.
• Use of an intrauterine device (IUD).
• Use of hormonal birth control, including birth control pills, Depo-Provera, and Implanon.
• Midcycle bleeding (ovulation).
• Pelvic or cervical infection.
• Breast-feeding.
• Hormonal imbalance.
• Thyroid disease.
• Sexual abuse.