Iron-Deficiency Anemia

Also known as
Iron-deficiency anemia is a common type of anemia that occurs if you do not have enough iron in your body. People with mild or moderate iron-deficiency anemia may not have any signs or symptoms. More severe iron-deficiency anemia may cause fatigue or tiredness, shortness of breath, or chest pain.

If your doctor diagnoses you with iron-deficiency anemia, your treatment will depend on the cause and severity of the condition. Your doctor may recommend healthy eating changes, iron supplements, intravenous iron therapy for mild to moderate iron-deficiency anemia, or red blood cell transfusion for severe iron-deficiency anemia. You may need to address the cause of your iron deficiency, such as any underlying bleeding. If undiagnosed or untreated, iron-deficiency anemia can cause serious complications, including heart failure and development delays in children.

Explore this Health Topic to learn more about iron-deficiency anemia, our role in research and clinical trials to improve health, and where to find more information.
Causes

Your body needs iron to make healthy red blood cells. Iron-deficiency anemia usually develops over time because your body’s intake of iron is too low. Low intake of iron can happen because of blood loss, consuming less than the recommended daily amount of iron, and medical conditions that make it hard for your body to absorb iron from the gastrointestinal tract (GI tract).

Blood loss

When you lose blood, you lose iron. Certain conditions or medicines can cause blood loss and lead to iron-deficiency anemia. Common causes of blood loss that lead to iron-deficiency anemia include:

  • Bleeding in your GI tract, from an ulcer, colon cancer, or regular use of medicines such as aspirin or nonsteroidal anti-inflammatory drugs (NSAIDS), such as ibuprofen and naproxen
  • Certain rare genetic conditions such as hereditary hemorrhagic telangiectasia, which causes bleeding in the bowels
  • Frequent blood donation
  • Frequent blood tests, especially in infants and small children
  • Heavy menstrual periods
  • Injury or surgery
  • Urinary tract bleeding

Iron-deficiency anemia can be caused by getting less than the recommended daily amounts of iron. The recommended daily amounts of iron will depend on your age, sex, and whether you are pregnant or breastfeeding.

Recommended daily iron intake for children and adults. The table lists the recommended amounts of iron, in milligrams (mg) at different ages and stages of life. Until the teen years, the recommended amount of iron is the same for boys and girls. From birth to 6 months, babies need 0.27 mg of iron. This number goes up to 11 mg for children ages 7 to 12 months, and down to 7 mg for children ages 1 to 3. From ages 4 to 8, children need 10 mg, and from ages 9 to 13, 8 mg. From ages 14 to 18, boys need 11 mg, while girls need 15 mg. From ages 19 to 50, men need 8 mg and women need 18 mg. After age 51, both men and women need 8 mg. Pregnant women need 27 mg. Breastfeeding girls under age 18 need 10 mg while breastfeeding women older than 18 need 9 mg.
Recommended daily iron intake for children and adults. The table lists the recommended amounts of iron, in milligrams (mg) at different ages and stages of life. Until the teen years, the recommended amount of iron is the same for boys and girls. From birth to 6 months, babies need 0.27 mg of iron. This number goes up to 11 mg for children ages 7 to 12 months, and down to 7 mg for children ages 1 to 3. From ages 4 to 8, children need 10 mg, and from ages 9 to 13, 8 mg. From ages 14 to 18, boys need 11 mg, while girls need 15 mg. From ages 19 to 50, men need 8 mg and women need 18 mg. After age 51, both men and women need 8 mg. Pregnant women need 27 mg. Breastfeeding girls under age 18 need 10 mg while breastfeeding women older than 18 need 9 mg.

Problems absorbing iron

Even if you consume the recommended daily amount of iron, your body may not be able to absorb the iron. Certain conditions or medicines can decrease your body’s ability to absorb iron and lead to iron-deficiency anemia. These conditions include:

  • Intestinal and digestive conditions, such as celiac disease; inflammatory bowel diseases, including ulcerative colitis and Crohn’s disease; and Helicobacter pylori infection.
  • A history of gastrointestinal surgery, such as weight-loss surgery—especially gastric bypass—or gastrectomy.
  • Certain rare genetic conditions, such as a TMRPSS6 gene mutation that causes a person’s body to make too much of a hormone called hepcidin. Hepcidin blocks the intestine from taking up iron.

Other medical conditions

Other medical conditions that may lead to iron-deficiency anemia include:

  • End-stage kidney failure, where there is blood loss during dialysis. People who have chronic kidney disease also often take other medicines—such as proton pump inhibitors, anticoagulants, or blood thinners—that may cause iron-deficiency anemia. Proton pump inhibitors interfere with iron absorption, and blood thinners increase the likelihood of bleeding in the GI tract.
  • Inflammation from congestive heart failure or obesity. These chronic conditions can lead to inflammation that may cause iron-deficiency anemia.

Are you curious about how inflammation from chronic diseases can cause iron-deficiency anemia?

Look for

  • Treatment will discuss medicines and eating pattern changes that your doctors may recommend if you are diagnosed with iron-deficiency anemia.
Risk Factors

You may have an increased risk for iron-deficiency anemia because of your age, unhealthy environments, family history and genetic, lifestyle habits, or sex.

Age

You may be at increased risk for iron deficiency at certain ages:

  • Infants between 6 and 12 months, especially if they are fed only breast milk or are fed formula that is not fortified with iron. The iron that full-term infants have stored in their bodies is used up in the first 4 to 6 months of life. Babies who were born prematurely may be at an even higher risk, as most of a newborn’s iron stores are developed during the third trimester of pregnancy.
  • Children between ages 1 and 2, especially if they drink a lot of cow’s milk. Cow’s milk is low in iron. 
  • Teens, who have increased need for iron during growth spurts.
  • Older adults, especially those over age 65.

Unhealthy environments

  • Children who have lead in their blood from their environment or water. Lead interferes with the body’s ability to make hemoglobin.

Family history and genetics

Von Willebrand disease is an inherited bleeding disorder that affects the blood’s ability to clot. This makes it harder to stop bleeding and can increase the risk of iron-deficiency anemia from trauma, surgery, or heavy menstrual periods.

Individuals with a gene for hemophilia, including symptomatic female carriers who have heavy menstrual periods, may be at risk for iron-deficiency anemia.

Lifestyle habits

Certain lifestyle habits may increase your risk for iron-deficiency anemia, including:

  • Vegetarian or vegan eating patterns. Not eating enough iron-rich foods, such as meat and fish, may result in you getting less than the recommended daily amount of iron.
  • Frequent blood donation. Individuals who donate blood often may be at risk for iron-deficiency anemia.
  • Endurance activities and athletes. Athletes, especially young females, are at risk for iron deficiency. Endurance athletes lose iron through their gastrointestinal tracts. They also lose iron through the breakdown of red blood cells, called hemolysis. Hemolysis, in this case, is caused by strong muscle contractions and the impact of feet repeatedly striking the ground, such as with marathon runners.

Sex

Girls and women between the ages of 14 and 50 years need more iron than boys and men of the same age. Women are at higher risk for iron-deficiency anemia under some circumstances, including:

  • During menstruation, especially if you experience heavy periods.
  • During pregnancy, after delivery, or when breastfeeding you may be consuming less than the recommended daily amount of iron. This is because your need for iron increases during these periods of growth and development, and it may be hard to get the recommended amount from food alone. Pregnant women need more iron to support the growth of their unborn babies, so their bodies produce more blood. With more red blood cells on hand, their bodies can store iron to prepare for blood loss during delivery. 
Screening and Prevention

Your doctor may screen you for iron-deficiency anemia if you have certain risk factors, including pregnancy. To prevent iron-deficiency anemia, your doctor may recommend you eat heart-healthy foods or control other conditions that can cause iron-deficiency anemia.

Blood tests to screen for iron-deficiency anemia

To screen for iron-deficiency anemia, your doctor may order a blood test called a complete blood count (CBC) to see if you have lower than normal red blood cell counts, hemoglobin or hematocrit levels, or mean corpuscular volume (MCV) that would suggest anemia.

Different tests help your doctor screen for iron-deficiency anemia. A complete blood count measures hemoglobin and mean corpuscular volume (MCV). Hemoglobin of less than 13 grams per deciliter (g/dl) for men and less than 12 g/dl for women is diagnostic of anemia. In iron-deficiency anemia, red blood cells will be small in size with an MCV of less than 80 femtoliters (fL).
Different tests help your doctor screen for iron-deficiency anemia. A complete blood count measures hemoglobin and mean corpuscular volume (MCV). Hemoglobin of less than 13 grams per deciliter (g/dl) for men and less than 12 g/dl for women is diagnostic of anemia. In iron-deficiency anemia, red blood cells will be small in size with an MCV of less than 80 femtoliters (fL).

Prevention strategies

If you have certain risk factors, such as if you are following a vegetarian eating pattern, your doctor may recommend changes to help you meet the recommended daily amount of iron. If you have other medical conditions that cause iron-deficiency anemia, such as bleeding in the digestive or urinary tract or heavy menstrual bleeding, your doctor will want to control these other conditions to prevent you from developing iron-deficiency anemia.

  • Foods that are good sources of iron include dried beans, dried fruits, eggs, lean red meat, salmon, iron-fortified breads and cereals, peas, tofu, dried fruits, and dark green leafy vegetables.
  • Foods rich in vitamin C, such as oranges, strawberries, and tomatoes, may help increase your absorption of iron.

If you are pregnant, talk to your doctor about delayed clamping of your newborn’s umbilical cord at the time of delivery. This may help prevent iron-deficiency anemia in your newborn for both full-term and preterm infants.

Look for

  • Diagnosis will explain tests and procedures that your doctor may use to diagnose iron-deficiency anemia.
  • Living With will discuss what your doctor may recommend to prevent your iron-deficiency anemia from recurring, getting worse, or causing complications.
  • Research for Your Health will explain how we are using current research and advancing research to prevent iron-deficiency anemia.
  • Participate in NHLBI Clinical Trials will explain our ongoing clinical studies that are investigating prevention strategies for iron-deficiency anemia.
Signs, Symptoms, and Complications

Iron-deficiency anemia can range from mild to severe. People with mild or moderate iron-deficiency anemia may not have any sign or symptom. Symptoms generally worsen as anemia becomes more severe. If left untreated, iron deficiency can cause complications and may be life-threatening.

Signs and Symptoms

Common signs of iron-deficiency anemia include:

  • Brittle nails or spooning of the nails
  • Cracks at the sides of the mouth
  • Pale skin
  • Swelling or soreness of the tongue

Common symptoms of iron-deficiency anemia include: 

  • Chest pain
  • Coldness in the hands and feet
  • Difficulty concentrating
  • Dizziness
  • Fatigue, or feeling tired, is the most common symptom. This can make it hard to find the energy to do normal activities.
  • Headache
  • Irregular heartbeat. This is a sign of more serious iron-deficiency anemia.
  • pica, which are unusual cravings for nonfood items, such as ice, dirt, paint, or starch.
  • Restless legs syndrome
  • Shortness of breath
  • Weakness

Complications

Undiagnosed or untreated iron-deficiency anemia may cause the following complications:

  • Depression
  • Heart problems. If you do not have enough hemoglobin-carrying red blood cells, your heart has to work harder to move oxygen-rich blood through your body. Cells in tissues need a steady supply of oxygen to work well. Normally, hemoglobin in red blood cells takes up oxygen in the lungs and carries it to all the tissues of the body. When your heart has to work harder, this can lead to several conditions: irregular heartbeats called arrhythmias, a heart murmur, an enlarged heart, or even heart failure.
  • Increased risk of infections
  • Motor or cognitive development delays in children
  • Pregnancy complications, such as preterm delivery or giving birth to a baby with low birth weight

In people with chronic conditions, iron-deficiency anemia can make their condition worse or result in treatments not working as well.

Look for

  • Diagnosis will discuss any procedures used to detect signs of iron-deficiency anemia and help rule out other types of anemia.
  • Treatment will explain treatment-related complications or side effects.
Diagnosis

Iron-deficiency anemia may be detected during routine blood tests when you visit your doctor for a checkup. To diagnose iron-deficiency anemia, your doctor may ask you questions about your risk factors, do a physical exam, or order blood tests or other diagnostic tests.

Physical exam

Your doctor may ask about your medical history and any symptoms you are experiencing, and do a physical exam to look for any of the following signs that may help diagnose iron-deficiency anemia:

  • Check for bleeding.
  • Look to see whether your tongue, nails, or inner lining of your eyelids are pale.
  • Check your fingernails to see whether they are pale or brittle, and how quickly they refill with blood.
  • Listen to your heart for rapid or irregular heartbeats.
  • Listen to your lungs for rapid or uneven breathing.
  • Feel your abdomen to check the size of your liver and spleen.

Blood tests

Based on results from blood tests to screen for iron-deficiency anemia, your doctor may order the following blood tests to diagnose iron-deficiency anemia:

  • Complete blood count (CBC) to see if you have lower than normal red blood cell counts, hemoglobin or hematocrit levels, or mean corpuscular volume (MCV) that would suggest anemia.
  • Iron to measure the amount of iron in your blood. The level of iron in your blood may be normal even if the total amount of iron in your body is low. For this reason, other iron tests are also done.
  • Ferritin measure to find out how much of your body’s stored iron has been used. Ferritin is a protein that helps store iron in your body.
  • Reticulocyte count to see if you have lower than normal numbers of these very young red blood cells.
  • Peripheral smear to see if your red blood cells look smaller and paler than normal when viewed under a microscope.
Different tests help your doctor diagnose iron-deficiency anemia. In iron-deficiency anemia, blood levels of iron will be low, or less than 10 micromoles per liter (mol/L) for both men and women. Normal levels are 10 to 30 mol/L. Levels of ferritin will also be low, or less than 10 micrograms per liter (g/L) for both men and women. Normal levels are 40 to 300 for men and 20 to 200 for women.
Different tests help your doctor diagnose iron-deficiency anemia. In iron-deficiency anemia, blood levels of iron will be low, or less than 10 micromoles per liter (mmol/L) for both men and women. Normal levels are 10 to 30 mmol/L. Levels of ferritin will also be low, or less than 10 micrograms per liter (mg/L) for both men and women. Normal levels are 40 to 300 for men and 20 to 200 for women.

To help diagnose iron-deficiency anemia, your doctor will consider your CBC, hemoglobin, blood iron levels, MCV, and ferritin levels to determine if you have iron-deficiency anemia or another type of anemia. You may be diagnosed with iron-deficiency anemia if you have low iron or ferritin levels in your blood.

More testing may be needed to rule out other types of anemia.

Tests for gastrointestinal bleeding

To see if gastrointestinal bleeding is causing your iron-deficiency anemia, your doctor may order the following procedures to guide treatment.

  • Fecal occult blood test to check for blood in the stool. Blood in the stool would suggest bleeding in the GI tract and may require further testing.
  • Upper endoscopy to look for bleeding in the esophagus, stomach, and the first part of the small intestine. A tube with a tiny camera is inserted through your mouth down to your stomach and upper small intestine to view the lining of your upper digestive tract.
  • Colonoscopy to look for bleeding or other abnormalities, such as growths or cancer of the lining of the colon. For this test, a small camera is inserted into the colon under sedation to view the colon directly.

What if my doctor thinks something else is causing my iron-deficiency anemia?

Reminders

  • Return to Causes to review how blood loss, not consuming the recommended amount of iron, and medical conditions can lead to iron-deficiency anemia. 
  • Return to Risk Factors to review family history, lifestyle, unhealthy environments, or other factors that increase your risk of developing iron-deficiency anemia.
  • Return to Signs, Symptoms, and Complications to review common signs and symptoms of iron-deficiency anemia.
  • Return to Screening and Prevention to review tests to screen for and strategies to prevent iron-deficiency anemia.
Treatment

Treatment for iron-deficiency anemia will depend on its cause and severity. Treatments may include iron supplements, procedures, surgery, and dietary changes. Severe iron-deficiency anemia may require intravenous (IV) iron therapy or a blood transfusion.

Iron supplements

Your doctor may recommend that you take iron supplements, also called iron pills or oral iron, by mouth once or several times a day to increase the iron in your body. This is the most common treatment for iron deficiency. It generally takes three to six months to replenish your iron stores.

Iron supplements are sometimes recommended by your doctor during pregnancy. If your condition is caused by certain rare genetic conditions, such as a TMRPSS6 gene mutation, you may not respond to oral iron supplements.

Iron supplements are generally not recommended for people who do not have iron-deficiency anemia. This is because too much iron can damage your organs.

Do not stop taking your prescribed iron supplements without first talking to your doctor. Talk to your doctor if you are experiencing side effects such as a bad metallic taste, vomiting, diarrhea, constipation, or upset stomach. Your doctor may be able to recommend options such as taking your supplements with food, lowering the dose, trying a different type of iron supplement, or receiving intravenous (IV) iron.

Procedures

If iron supplements alone are not able to replenish the levels of iron in your body, your doctor may recommend a procedure, including:

  • Iron therapy, or intravenous (IV) iron. This is sometimes used to deliver iron through a blood vessel to increase iron levels in the blood. One benefit of IV iron is that it often takes only one or a few sessions to replenish the amount of iron in your body. People with severe iron-deficiency anemia or who have chronic conditions such as kidney disease or celiac disease may be more likely to receive IV iron. You may experience vomiting, headache, or other side effects right after the IV iron, but these usually go away within a day or two.
  • Red blood cell transfusions. These may be used for people with severe iron-deficiency anemia to quickly increase the amount of red blood cells and iron in the blood. Your doctor may recommend this if you have serious complications of iron-deficiency anemia, such as chest pain.
  • Surgery, upper endoscopy or colonoscopy, to stop bleeding.

Healthy lifestyle changes

To help you meet your daily recommended iron levels, your doctor may recommend that you:

  • Adopt healthy lifestyle changes such as heart-healthy eating patterns.
  • Increase your daily intake of iron-rich foods to help treat your iron-deficiency anemia. See Prevention strategies to learn about foods that are high in iron. It is important to know that increasing your intake of iron may not be enough to replace the iron your body normally stores but has used up.
  • Increase your intake of vitamin C to help your body absorb iron.
  • Avoid drinking black tea, which reduces iron absorption.

Other treatments

If you have chronic kidney disease and iron-deficiency anemia, your doctor may recommend erythropoiesis stimulating agent (ESA). These medicines stimulate the bone marrow to make more red blood cells. ESAs are usually used with iron therapy or IV iron, or when iron therapy alone is not enough.

Look for

  • Living With will discuss what your doctor may recommend, including lifelong lifestyle changes and medical care to prevent your condition from recurring, getting worse, or causing complications.
  • Research for Your Health will discuss how we are using current research and advancing research to treat people with iron-deficiency anemia.
  • Participate in NHLBI Clinical Trials will highlight our ongoing clinical studies that are investigating treatments for iron-deficiency anemia.
Living With

After being diagnosed with iron-deficiency anemia, it is important to follow your treatment plan. Your doctor may recommend additional follow-up care and lifestyle changes to avoid complications.

Follow your treatment plan

Do not stop taking your prescribed iron supplements without first talking to your doctor. Talk to your doctor if you are experiencing side effects such as a bad metallic taste, vomiting, diarrhea, constipation, or upset stomach. Your doctor may be able to recommend options such as taking your supplement with food, lowering the dose, trying a different type of iron supplement, or receiving intravenous (IV) iron.

Monitor your condition

You may have fatigue and other symptoms of iron-deficiency anemia until your iron levels return to normal, which can take months. Tell your doctor if you have any new symptoms or if your symptoms get worse, especially if you experience chest pain or feel like your heart is beating irregularly.

Tell any doctors you see for other conditions that you have iron-deficiency anemia. Iron-deficiency anemia can make other conditions, such as HIV, worse or harder to treat. Tell your doctor what medicines you take, even over-the-counter medicines or other supplements. Iron supplements can change how certain medicines work.

Your doctor may suggest check-ups to make sure your iron and hemoglobin levels are improving and staying at healthy levels. Your doctor may:

  • Ask about your signs and symptoms, including whether you have any new or worsening symptoms.
  • Repeat blood tests, such as complete blood count and iron studies.

Prevent complications over your lifetime

To prevent complications from iron-deficiency anemia, your doctor may recommend heart-healthy eating and choosing iron-rich foods, especially during certain stages of life when more iron is needed, such as childhood and pregnancy. Good sources of iron are meat, poultry, fish, and iron-fortified foods that have iron added.

Vegetarian diets can provide enough iron if you choose nonmeat sources of iron, including iron-fortified breads and cereals, beans, tofu, dried fruits, and spinach and other dark green leafy vegetables. You can also take an iron supplement.

Follow your doctor’s recommendations and treatments to control any conditions that lead to iron-deficiency anemia to prevent complications such as abnormal heart rhythms and depression.

Learn the warning signs of serious complications and have a plan

Tell your doctor if you have any new symptoms or if your symptoms get worse, especially if you experience chest pain or feel your heart is beating irregularly.

Learn about other precautions to help you stay safe

Talk to your doctor about returning to everyday activities. Because iron-deficiency anemia can make you feel weak, you should be cautious when resuming certain activities, such as physical activity. Older adults, who are more likely to fall, should be especially cautious when resuming activities.

Reminders

Research for Your Health

The NHLBI is part of the U.S. Department of Health and Human Services’ National Institutes of Health (NIH)—the Nation’s biomedical research agency that makes important scientific discoveries to improve health and save lives. We are committed to advancing science and translating discoveries into clinical practice to promote the prevention and treatment of heart, lung, blood, and sleep disorders, including iron-deficiency anemia. Learn about the current and future NHLBI efforts to improve health through research and scientific discovery.

Improving health with current research

Learn about the following ways that NHLBI continues to translate current research into improved health for people with iron-deficiency anemia.

  • Recipient Epidemiology Donor Studies program findings help to protect blood donors. NHLBI’s Recipient Epidemiology Donor Studies (REDS) program, which began in 1989 to protect the nation’s blood supply and improve transfusions, found that many people, especially women, who frequently donate blood have low or depleted levels of iron stored in their body. This is the largest study to have looked at iron levels in blood donors. Results from the REDS program have led to other research and newer recommendations to increase the length of time between donations to protect blood donors.
  • Cardiovascular Health Study identifies predictors of future health problems in older adults. The NHLBI-sponsored Cardiovascular Health Study found that many older adults over 65 years of age had low hemoglobin levels. This was associated with a greater risk of death even with mild anemia. Now, anemia in older adults is recognized as an important condition.
  • NHLBI Small Business Program. Through the NHLBI Small Business Program, we fund research and development for domestic small businesses that have strong potential for technology commercialization through the Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) programs. Our support of SBIR/STTR programs is helping advance research in iron-deficiency anemia, in part by funding ways to screen blood donors for low iron stores. Reliable point-of-care testing may help identify iron deficiency before potentially harmful donations and protect individuals from needing iron supplementation.

Advancing research for improved health

In support of our mission, we are committed to advancing research on anemia, in part through the following ways.

Learn about exciting research areas that NHLBI is exploring about iron-deficiency anemia.

Participate in NHLBI Clinical Trials

We lead or sponsor many studies related to iron-deficiency anemia. See if you or someone you know is eligible to participate in our clinical trials.

Are you a frequent blood donor living in New York City?

This study is looking at how iron-deficiency anemia in blood donors affects the quality of donated red blood cells, such as how well the red blood cells survive after transfusion. To participate, your blood must meet certain requirements and you must be healthy, 18 to 75 years old, weigh more than 110 pounds, and donate blood frequently. This study is located in New York City, and is recruiting by invitation only.
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