Munson Health
Conditions InDepth: Menstrual Disorders: Heavy Bleeding (Menorrhagia) and Absence of Menstruation (Amenorrhea)

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by Neff DM
Menstrual disorders consist of changes in the normal menstruation process.
Menstrual Flow
Copyright © Nucleus Medical Media, Inc.

Normal Menstruation

Heavy Menstrual Bleeding

Most women lose an average of about 2 ounces (60 milliliters [mL]) of blood or less during normal menstruation. However, in some women, menstrual bleeding can be significantly heavier and/or longer. This is called menorrhagia. This happens if you lose more than 80 mL of blood and have a period lasting for more than seven days. This can be caused by a number of conditions and can lead to anemia and other complications.

Absence of Menstruation

The absence of menstruation is categorized as primary or secondary. Primary amenorrhea occurs when a girl does not start to menstruate within the normal time frame of sexual development. Primary amenorrhea is diagnosed if there is no menses by age 14 in the absence of growth or development of secondary sexual characteristics; or if there is no menses by age 16 regardless of presence of normal growth and development with the appearance of secondary sexual characteristics.
Secondary amenorrhea occurs when previously initiated menstrual periods are absent for at least three cycles (for reasons other than menopause).
Amenorrhea can be caused by:
  • Pregnancy
  • Hormonal imbalances
  • Hypothyroidism
  • Hyperprolactinemia (high levels of prolactin in the blood)
  • Eating disorders
  • Psychiatric disorders
  • Low or high body fat
  • Rapid weight loss
  • Excessive exercise or intense physical training
  • Other conditions
Due to the underlying low estrogen, prolonged amenorrhea can lead to a decrease in bone density and an increased risk of osteoporosis.

Other Possible Types of Abnormal Bleeding

Less commonly, women may ovulate, but changes in the length of the follicular phase or other conditions can cause:
  • Polymenorrhea—too many menses close together (less than typical 21 days)
  • Oligomenorrhea—too few cycles (menses far apart)
Possible Causes of Abnormal Bleeding
There are many causes of abnormal bleeding. Examples of causes include:
  • Complications of pregnancy
  • Trauma
  • Infection
  • Medicines (including intrauterine devices and birth control pills)
  • Treatments and conditions (for example, fibroids, polyps, cancer, in rare cases)
  • Stress, exercise, and other conditions—These can stop the normal cycle of ovulation.


Amenorrhea. EBSCO DynaMed website. Available at: Updated January 21, 2011. Accessed August 20, 2012.

Heavy menstrual bleeding. EBSCO DynaMed website. Available at: Updated 25, 2012. Accessed August 20, 2012.

Menstruation and the menstrual cycle fact sheet. Womens website. Available at: Updated October 21, 2009. Accessed August 20, 2012.


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