Iron Deficiency Anemia

Medically reviewed by Shuvani Sanyal, MD on July 17, 2017Written by Jacquelyn Cafasso and Rachel Nall

What is iron deficiency anemia?

Anemia occurs when you have a decreased level of hemoglobin in your red blood cells (RBCs). Hemoglobin is the protein in your RBCs that is responsible for carrying oxygen to your tissues.

Iron deficiency anemia is the most common type of anemia, and it occurs when your body doesn’t have enough of the mineral iron. Your body needs iron to make hemoglobin. When there isn’t enough iron in your blood stream, the rest of your body can’t get the amount of oxygen it needs.

While the condition may be common, many people don’t know they have iron deficiency anemia. It’s possible to experience the symptoms for years without ever knowing the cause.

In women of childbearing age, the most common cause of iron deficiency anemia is a loss of iron in the blood due to heavy menstruation or pregnancy. A poor diet or certain intestinal diseases that affect how the body absorbs iron can also cause iron deficiency anemia.

Doctors normally treat the condition with iron supplements or changes to diet.

Symptoms of iron deficiency anemia

The symptoms of iron deficiency anemia can be mild at first, and you may not even notice them. According to the American Society of Hematology (ASH), most people don’t realize they have mild anemia until they have a routine blood test.

The symptoms of moderate to severe iron deficiency anemia include:

Causes of iron deficiency anemia

According to the ASH, iron deficiency is the most common cause of anemia. There are many reasons why a person might become deficient in iron. These include:

Inadequate iron intake

Eating too little iron over an extended amount of time can cause a shortage in your body. Foods such as meat, eggs, and some green leafy vegetables are high in iron. Because iron is essential during times of rapid growth and development, pregnant women and young children may need even more iron-rich foods in their diet.

Pregnancy or blood loss due to menstruation

Heavy menstrual bleeding and blood loss during childbirth are the most common causes of iron deficiency anemia in women of childbearing age.

Internal bleeding

Certain medical conditions can cause internal bleeding, which can lead to iron deficiency anemia. Examples include an ulcer in your stomach, polyps in the colon or intestines, or colon cancer. Regular use of pain relievers, such as aspirin, can also cause bleeding in the stomach.

Inability to absorb iron

Certain disorders or surgeries that affect the intestines can also interfere with how your body absorbs iron. Even if you get enough iron in your diet, celiac disease or intestinal surgery such as gastric bypass may limit the amount of iron your body can absorb.

Risk factors

Anemia is a common condition and can occur in both men and women of any age and from any ethnic group. Some people may be at greater risk of iron deficiency anemia than others, including:

  • women of childbearing age
  • pregnant women
  • people with poor diets
  • people who donate blood frequently
  • infants and children, especially those born prematurely or experiencing a growth spurt
  • vegetarians who don’t replace meat with another iron-rich food

If you’re at risk of iron deficiency anemia, talk to your doctor to determine if blood testing or dietary changes could benefit you.

How it’s diagnosed

A doctor can diagnose anemia with blood tests. These include:

Complete blood cell (CBC) test

A complete blood count (CBC) is usually the first test a doctor will use. A CBC measures the amount of all components in the blood, including:

The CBC provides information about your blood that is helpful in diagnosing iron deficiency anemia. This information includes:

  • the hematocrit level, which is the percent of blood volume that is made up of RBCs
  • the hemoglobin level
  • the size of your RBCs

A normal hematocrit range is 34.9 to 44.5 percent for adult women and 38.8 to 50 percent for adult men. The normal hemoglobin range is 12.0 to 15.5 grams per deciliter for an adult woman and 13.5 to 17.5 grams per deciliter for an adult man.

In iron deficiency anemia, the hematocrit and hemoglobin levels are low. Also, RBCs are usually smaller in size than normal.

A CBC test is often performed as part of a routine physical examination. It’s a good indicator of a person’s overall health. It may also be performed routinely before a surgery. This test is useful to diagnose this type of anemia because most people who have an iron deficiency don’t realize it.

Other tests

Anemia can usually be confirmed with a CBC test. Your doctor might order additional blood tests to determine how severe your anemia is and help determine treatments. They may also examine your blood through a microscope. These blood tests will provide information, including:

Ferritin is a protein that helps with iron storage in your body. Low levels of ferritin indicate low iron storage. A TIBC test is used to determine the amount transferrin that’s carrying iron. Transferrin is a protein that transports iron.

Tests for internal bleeding

If your doctor is concerned that internal bleeding is causing your anemia, additional tests may be needed. One test you may have is fecal occult test to look for blood in your feces. Blood in your feces may indicate bleeding in your intestine.

Your doctor may also perform an endoscopy, in which they use a small camera on a flexible tube to view the linings of your gastrointestinal tract. An EGD test, or upper endoscopy, allows a doctor to examine the lining of the esophagus, stomach, and the upper part of the small intestine. A colonoscopy, or lower endoscopy, allows a doctor to examine the lining of the colon, which is the lower portion of the large intestine. These tests can help identify sources of gastrointestinal bleeding.

Iron deficiency anemia in women

Pregnancy, significant menstrual bleeding, and uterine fibroids are all reasons why women are more likely to experience iron deficiency anemia.

Heavy menstrual bleeding occurs when a woman bleeds more or longer than women typically bleed during menstruation. According to the Centers for Disease Control and Prevention, typical menstrual bleeding lasts for 4 to 5 days and the amount of blood lost ranges from 2 to 3 tablespoons. Women with excess menstrual bleeding typically bleed for more than seven days and lose twice as much blood as normal.

According to the National Heart, Lung, and Blood Institute, an estimated 20 percent of women of childbearing age have iron deficiency anemia. Pregnant women are even more likely to have iron deficiency anemia because they require greater amounts of blood to support their growing babies.

A pelvic ultrasound can help a doctor look for the source of excess bleeding during a woman’s period, such as fibroids. Like iron deficiency anemia, uterine fibroids often don’t cause symptoms. They occur when muscular tumors grow in the uterus. While they’re not usually cancerous, they can cause heavy menstrual bleeding that can lead to iron deficiency anemia.

Health complications of iron deficiency anemia

Most cases of iron deficiency anemia are mild and don’t cause complications. The condition can usually be corrected easily. However, if anemia or iron deficiency is left untreated, it can lead to other health problems. These include:

Rapid or irregular heartbeat

When you’re anemic, your heart has to pump more blood to make up for the low amount of oxygen. This can lead to irregular heartbeat. In severe cases, it can lead to heart failure or an enlarged heart.

Pregnancy complications

In severe cases of iron deficiency, a child may be born prematurely or with a low birth weight. Most pregnant women take iron supplements as part of their prenatal care to prevent this from happening.

Delayed growth in infants and children

Infants and children who are severely deficient in iron may experience delayed growth and development. They may also be more prone to infections.

Treatment options

Iron supplements

Iron tablets can help restore iron levels in your body. If possible, you should take iron tablets on an empty stomach, which helps the body absorb them better. If they upset your stomach, you can take them with meals. You may need to take the supplements for several months. Iron supplements may cause constipation or black stools.

Diet

Diets that include the following foods can help treat or prevent iron deficiency:

  • red meat
  • dark green, leafy vegetables
  • dried fruits
  • nuts
  • iron-fortified cereals

Additionally, vitamin C helps your body absorb iron. If you’re taking iron tablets, a doctor might suggest taking the tablets along with a source of vitamin C, such as a glass of orange juice or citrus fruit.

Treating the underlying cause of bleeding

Iron supplements won’t help if excess bleeding causes the deficiency. A doctor may prescribe birth control pills to women who have heavy periods. This can reduce the amount of menstrual bleeding each month.

In the most severe cases, a blood transfusion can replace iron and blood loss quickly.

Prevention

When caused by inadequate iron intake, iron deficiency anemia can be prevented by eating a diet high in iron-rich foods and vitamin C. Mothers should make sure to feed their babies breast milk or iron-fortified infant formula.

Foods high in iron include:

  • meat, such as lamb, pork, chicken, and beef
  • beans
  • pumpkin and squash seeds
  • leafy greens, such as spinach
  • raisins and other dried fruit
  • eggs
  • seafood, such as clams, sardines, shrimp, and oysters
  • iron-fortified dry and instant cereals

Foods high in vitamin C include:

  • fruits such as oranges, grapefruits, strawberries, kiwis, guavas, papayas, pineapples, melons, and mangoes
  • broccoli
  • red and green bell peppers
  • Brussels sprouts
  • cauliflower
  • tomatoes
  • leafy greens

Outlook for iron deficiency anemia

Diagnosing and treating iron deficiency anemia by yourself can result in adverse health effects due to too much iron in your blood. The complications from too much iron in your blood include liver damage and constipation. If you have symptoms of iron deficiency anemia, talk to your doctor instead.

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