Conditions InDepth: Menstrual Disorders: Heavy Bleeding (Menorrhagia) and Absence of Menstruation (Amenorrhea)
by Cynthia M. Johnson, MA
Menstrual disorders are changes in normal menstruation.
Menstruation is one part of the cycle in which a woman's body gets ready for pregnancy each month. A cycle is counted from the first day of bleeding to the first day of the next period. An average cycle is 28 days, but 21-35 days is also common.
At the start of the cycle, the hormones estrogen and progesterone are low. As the cycle continues, estrogen starts to rise. This makes the lining of the womb grow and thicken. An egg in one of the ovaries also starts to mature. It is in a follicle sac that makes estrogen as the egg grows.
At about day 14 of a 28-day cycle, the sac bursts and the egg leaves the ovary. It stays near the opening of the fallopian tube until it is fertilized by a male sperm. If this happens, it travels through one of the tubes to the womb. Ovulation is when the egg leaves the ovary.
After the egg leaves, the sac (now called the corpus luteum) stays in the ovary. It keeps making hormones, mainly progesterone. The rising levels of estrogen and progesterone help build up the lining of the womb to get ready for pregnancy.
The few days before, during, and after ovulation is the time when a woman can become pregnant. Because the length of cycles varies, it may happen earlier or later than day 14. The sac keeps making hormones only for 14 days, unless the egg is fertilized by sperm.
The fertilized egg becomes an embryo, passes down the fallopian tube, and attaches to the lining of the womb. The growing pregnancy releases a hormone (hCG), which stimulates the corpus luteum. It makes all the progesterone needed to keep the egg implanted and growing until a placenta (an organ connecting the fetus to the mother) forms. The placenta then makes hormones and gives nourishment from the mother to the growing embryo.
If an egg is not fertilized, the corpus luteum stops making hormones and gets reabsorbed in the ovary. Estrogen and progesterone levels drop again, the lining of the womb breaks down, bleeding starts, and the cycle starts again.
This cycle will happen each month starting from about age 12 years old to an average age of 51 years old. This is when menopause signals the end of these cycles and being able to become pregnant.
Most women lose about two ounces (60 milliliters [mL]) of blood or less. In some women, bleeding can be heavier and last longer. This is called menorrhagia. This happens with more than 2.70 ounces (80 mL) of blood loss or periods that last more than seven days. This can be caused by a number of reasons. It can lead to anemia and other health problems.
The absence of menstruation can be primary or secondary. Primary amenorrhea is 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 without growth or development of secondary sexual characteristics; or if there is no menses by age 16 whether or not there is normal growth and development with the appearance of secondary sexual characteristics.
Secondary amenorrhea is when periods are absent for at least three cycles (for reasons other than menopause).
It can be caused by:
When estrogen is low, amenorrhea can lead to a decrease in bone density and an higher risk of osteoporosis.
Other types of abnormal bleeding are:
Less commonly, women may ovulate, but changes in the length of the follicular phase or other health problems can cause:
Some Causes of Abnormal Bleeding
Some causes of abnormal bleeding are:
This in-depth report focuses on menorrhagia and amenorrhea.
Abnormal uterine bleeding. EBSCO DynaMed Plus website. Available at: http://www.dynamed.... Updated August 24, 2018. Accessed October 29, 2018.
Amenorrhea. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T116009/Amenorrhea. Updated January 16, 2018. Accessed October 29, 2018.
Klein DA, Poth MA. Amenorrhea: an approach to diagnosis and management. Am Fam Physician. 2013 Jun 1;87(11):781-788.
Menstruation and the menstrual cycle fact sheet. Office on Women's Health website. Available at:
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Updated April 25, 2018. Accessed October 29, 2018.
Last reviewed September 2018 by EBSCO Medical Review BoardBeverly Siegal, MD, FACOG
Last Updated: 10/30/2018
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