Anemia: Is it due to excessive bleeding?

Anemia that develops due to significant bleeding occurs when the amount of red blood cells lost via bleeding exceeds the production of new red blood cells.

Undue bleeding is the usual reason for anemia. Once there is blood loss, the body rapidly draws out water from the tissues separate from the bloodstream in an effort to keep the blood vessels filled. This results to diluted blood and the hematocrit is lessened. After some time, the increased production of red blood cells by the bone marrow can correct the anemia. Nevertheless, over time, the bleeding lessens the amount of iron in the body, thus the bone marrow could not increase the production of new red blood cells to replace those that were lost.

What happens during rapid blood loss?

The symptoms might be initially severe particularly if anemia develops rapidly from abrupt blood loss such as from injuries, childbirth, surgery or a ruptured blood vessel. The loss of large amounts of blood abruptly can result to 2 issues:

  • Blood pressure drops since the amount of fluid left in the blood vessels are inadequate.
  • Oxygen supply of the body is drastically diminished since the amount of oxygenated red blood cells has rapidly decreased.

Chronic blood loss


Dizziness while standing or sitting after a period of lying down is common if the blood loss is rapid.

Chronic or long-term bleeding can occur from various regions in the body. Even though significant bleeding from nosebleed and hemorrhoids are evident, small amounts of bleeding might not be noticed.

An example is a small amount of blood visible in the stool. This type of blood loss is described as occult. In case a small amount of bleeding persists for a long period, large amount of blood is lost. This gradual bleeding can occur with common disorders such as ulcers in the stomach or small intestines, polyps, diverticulitis or cancer in the large intestines.


The symptoms are somewhat similar to the other forms of anemia and vary from mild to severe depending on the amount of blood lost and how rapidly. If the blood loss is rapid or occurs for several hours, it can be deadly.

Dizziness while standing or sitting after a period of lying down is common if the blood loss is rapid. If the blood loss is slower or occur for several weeks, it can result to fatigue and weakness or no symptoms at all if enough fluids is consumed.

The other symptoms can occur from bleeding or disorders that causes bleeding. There might be black, tarry stools if bleeding originates from the stomach or small intestine.

Bleeding from the bladder or kidneys can lead to brownish or reddish urine. Women might experience prolonged, heavy menstrual periods.


When dealing with significant or rapid blood loss, the source of bleeding should be determined and stopped. In some cases, transfusion of red blood cells might be required.

With minor blood loss, the body might generate enough red blood cells to fix anemia without the need for blood transfusions. Since iron which is needed to produce red blood cells is lost during bleeding, many who have anemia from bleeding make require iron supplements usually in tablet form for a number of months.