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"Anemia" (uh-NEE-mee-uh) occurs when you have less than the normal number of red blood cells in your blood or when the red blood cells in your blood don't have enough hemoglobin (HEE-muh-gloh-bin). Hemoglobin is a protein. It gives the red color to your blood. Its main job is to carry oxygen from your lungs to all parts of your body. If you have anemia, your blood does not carry enough oxygen to all the parts of your body. Without oxygen, your organs and tissues cannot work as well as they should. More than 3 million people in the United States have anemia. Women and people with chronic diseases are at the greatest risk for anemia.
Anemia happens when:
There are many types of anemia, all with different causes:
A person can have a low iron level because of blood loss. In women, iron and red blood cells are lost when bleeding occurs from very heavy and long periods, as well as from childbirth. Women also can lose iron and red blood cells from uterine fibroids, which can bleed slowly. Other ways iron and red blood cells can be lost include:
Eating foods low in iron also can cause IDA. Meat, poultry, fish, eggs, dairy products, or iron-fortified foods are the best sources of iron found in food. Pregnancy can cause IDA if a woman doesn't consume enough iron for both her and her unborn baby.
Vitamin B12 deficiency anemia (or pernicious [pur-NISH-us] anemia). This type of anemia happens due to a lack of vitamin B12 in the body. Your body needs vitamin B12 to make red blood cells and to keep your nervous system working normally. This type of anemia occurs most often in people whose bodies are not able to absorb vitamin B12 from food because of an autoimmune disorder. It also can happen because of intestinal problems.
You also can get this type of anemia if the foods you eat don't have enough vitamin B12. Vitamin B12 is found in foods that come from animals. Fortified breakfast cereals also have vitamin B12. Folic acid supplements (pills) can treat this type of anemia. But, folic acid cannot treat nerve damage caused by a lack of vitamin B12.
With this type of anemia, your doctor may not realize that you're not getting enough vitamin B12. Not getting enough vitamin B12 can cause numbness in your legs and feet, problems walking, memory loss, and problems seeing. The treatment depends on the cause. But you may need to get vitamin B12 shots or take special vitamin B12 pills.
Folate deficiency anemia. Folate, also called folic acid, is also needed to make red blood cells. This type of anemia can occur if you don't consume enough folate or if you have problems absorbing vitamins. It also may occur during the third trimester of pregnancy, when your body needs extra folate. Folate is a B vitamin found in foods such as leafy green vegetables, fruits, and dried beans and peas. Folic acid is found in fortified breads, pastas, and cereals.
Sickle cell anemia. The red blood cells of people with sickle cell disease are hard and have a curved edge. These cells can get stuck in the small blood vessels, blocking the flow of blood to the organs and limbs. The body destroys sickle red cells quickly. But, it can't make new red blood cells fast enough. These factors cause anemia.
Thalassemia (thal-uh-SEE-mee-uh). People with thalassemia make less hemoglobin and fewer red blood cells than normal. This leads to mild or severe anemia. One severe form of this condition is Cooley's anemia.
Aplastic (ay-PLAS-tik) anemia. This is a rare blood disorder in which the body stops making enough new blood cells. All blood cells — red cells, white cells, and platelets — are affected. Low levels of red blood cells leads to anemia. With low levels of white blood cells, the body is less able to fight infections. With too few platelets, the blood can't clot normally. This can be caused by many things:
Anemia takes some time to develop. In the beginning, you may not have any signs or they may be mild. But as it gets worse, you may have these symptoms:
All of these signs and symptoms can occur because your heart has to work harder to pump more oxygen-rich blood through the body.
Your doctor can tell if you have anemia by a blood test called a CBC. Your doctor also will do a physical exam and talk to you about the food you eat, the medicines you are taking, and your family health history. If you have anemia, your doctor may want to do other tests to find out what's causing it.
With any type of anemia, there are two treatment goals:
The treatment your doctor prescribes for you will depend on the cause of the anemia. For example, treatment for sickle cell anemia is different than treatment for anemia caused by low iron or folic acid intake. Treatment may include changes in foods you eat, taking dietary supplements (like vitamins or iron pills), changing the medicines you are taking, or in more severe forms of anemia, medical procedures such as blood transfusion or surgery.
Some types of anemia may be life threatening if not diagnosed and treated. Too little oxygen in the body can damage organs. With anemia, the heart must work harder to make up for the lack of red blood cells or hemoglobin. This extra work can harm the heart and even lead to heart failure.
There are steps you can take to help prevent some types of anemia.
Most people get enough iron by making healthy, balanced food choices and eating iron-rich foods. But some groups of people are at greater risk for low iron levels:
These groups of people should be screened at times for iron deficiency. If the tests show that the body isn't getting enough iron, iron pills (supplements) may be prescribed. In extreme cases of iron deficiency, your doctor might prescribe iron shots. Many doctors prescribe iron pills during pregnancy because many pregnant women don't get enough iron. Iron pills can help when diet alone can't restore the iron level back to normal. Talk with your doctor to find out if you are getting enough iron through the foods you eat or if you or your child needs to be taking iron pills. Please see the chart below to see how many milligrams (mg) of iron you should consume every day.
|Age||Infants and children||Women||Pregnant||Breastfeeding|
|7 to 12 months||11 mg||n/a||n/a||n/a|
|1 to 3 years||7 mg||n/a||n/a||n/a|
|4 to 8 years||10 mg||n/a||n/a||n/a|
|9 to 13 years||8 mg||n/a||n/a||n/a|
|14 to 18 years||n/a||15 mg||27 mg||10mg|
|19 to 50 years||n/a||18 mg||27 mg||9 mg|
|51+ years||n/a||8 mg||n/a||n/a|
Pregnant women need to consume twice as much iron as women who are not pregnant. But about half of all pregnant women do not get enough iron. During pregnancy, your body needs more iron because of the growing fetus, the higher volume of blood, and blood loss during delivery. If a pregnant woman does not get enough iron for herself or her growing baby, she has an increased chance of having preterm birth and a low-birth-weight baby. If you're pregnant, follow these tips:
It might. If you are still getting your period while taking MHT, you may need more iron than women who are postmenopausal and not taking MHT. Talk to your doctor.
It could. Some women who take birth control pills have less bleeding during their periods. This would lower their risk for anemia. But women who use an intrauterine device (IUD) may have more bleeding and increase their chances of getting anemia. Talk to your doctor.
It depends on the food choices you make. Since meat, poultry, and seafood are the best sources of iron found in food, some vegetarians may need to take a higher amount of iron each day than what is recommended for other people. Follow the tips above to prevent anemia, and try to take vitamin C with the iron-rich foods you eat.
Iron overload happens when too much iron builds up in the body over time. This condition is called hemochromatosis (HEE-moh-kroh-muh-TOH-suhss). The extra iron can damage the organs, mainly the liver, heart, and pancreas. Many problems can cause iron overload. Most people with hemochromatosis inherit it from their parents. It is one of the most common genetic (runs in families) diseases in the United States. Some other diseases also can lead to iron overload. It also can happen from years of taking too much iron or from repeated blood transfusions or dialysis for kidney disease.
Signs of early hemochromatosis may include:
As iron builds up in the body, common symptoms include:
Signs of advanced hemochromatosis include:
Treatment depends on how severe the iron overload is. The first step is to get rid of the extra iron in the body. Most people undergo a process called phlebotomy (fluh-BOT-uh-mee), which means removing blood. It is simple and safe. A pint of blood will be taken once or twice a week for several months to a year, and sometimes longer. Once iron levels go back to normal, you will give a pint of blood every 2 to 4 months for life. People who cannot give blood can take medicine to remove extra iron. This is called iron chelation (kuh-LAY-shuhn) therapy. Although treatment cannot cure the problems caused by hemochromatosis, it will help most of them. Arthritis is the only problem that does not improve after excess iron is removed.
For more information about anemia, call womenshealth.gov at 800-994-9662 (TDD: 888-220-5446) or contact the following organizations:
Anemia fact sheet was reviewed by:
Charles M. Peterson, M.D.
Director, Division of Blood Diseases and Resources
National Heart, Lung and Blood Institute
National Institutes of Health
Content last updated July 16, 2012.
Resources last updated May 13, 2008.