Anemia can be caused by blood loss, lack of red blood cell production and high rates of red blood cell destruction, according to the National Heart, Lung, and Blood Institute. A person with anemia does not have enough oxygen-rich blood and as a result, can feel tired or weak.
Blood loss is the most common cause of anemia and is usually in the form of iron-deficiency anemia, explains the National Heart, Lung, and Blood Institute. Some causes of blood loss include heavy menstrual periods, bleeding in the digestive or urinary tract, surgery, trauma and cancer. Blood transfusions and surgery may be needed to stop the blood loss and replenish the body.
A lack of red blood cell production can be caused by acquired and inherited conditions and factors, notes the National Heart, Lung, and Blood Institute. Aplastic anemia, an acquired or inherited condition, and a diet that lacks in certain nutrients such as iron both prevent the body from making enough red blood cells. Conditions such as hormonal imbalances, cancer and pregnancy can make it hard for the body to generate enough red blood cells. These conditions are treated in various ways including supplementation and bone marrow transplants.
High rates of red blood cell destruction can also be caused by acquired and inherited conditions, states the National Heart, Lung, and Blood Institute. An enlarged spleen, an acquired condition, may remove more red blood cells than normal and cause anemia. Inherited conditions such as sickle cell anemia and thalassemias create defects in the red blood cells that cause them to die faster than normal.