Severe or chronic anemia may lead to short- and long-term complications, including heart problems, infections, memory decline, limb tingling, and pregnancy risks, among others. Prompt diagnosis and treatment may prevent some of these.

While fatigue is the most recognized symptom of anemia, the condition may manifest with other symptoms and lead to health complications across multiple body systems. These complications may impact energy levels and also how your heart, brain, immune system, and other internal organs work.

The complications of anemia may depend on the type of anemia you have, but in general, they are more likely in older adults or people with compromised immune systems. Although rare, untreated severe anemia may lead to death in some cases.

The most common anemia complications include:

When blood doesn’t carry enough oxygen to the body’s tissues, the heart works harder to pump what little oxygen is available. If this happens for a long time, the extra workload on your heart may cause it to become larger and weaker.

Untreated or severe anemia may lead you to have a higher chance of developing heart problems, including heart failure and heart attacks.

Anemia may increase the chances of cerebrovascular complications, including stroke.

Iron deficiency anemia reduces how much oxygen your blood can carry, which may raise the risk of ischemic strokes.

Hemolytic anemia breaks red blood cells apart too early, releasing substances that may damage your blood vessels and may lead to thrombotic events (blood clots).

Anemia due to vitamin B12 deficiency may affect coagulation times (clotting), which is linked to hemorrhagic strokes (bleeding in the brain).

People with anemia who have had a stroke usually have delayed recovery times and may experience more serious brain damage and higher mortality rates compared to people who have a stroke but have no anemia.

In sum, people with anemia may be more likely to have a stroke, may have a slower recovery if they do, and could have more chances of long-term damage or death from the stroke event.

Anemia may also affect your immune system, weakening your defenses against viruses and bacteria.

If you have untreated or severe anemia, you may be more likely to develop local or systemic infections like pneumonia. You may also have a delayed recovery from chronic conditions or surgery.

Anemia in childhood may impair brain development. Iron deficiency anemia has been linked to delays in movement, language, and learning skills. These delays may not resolve even after anemia treatment.

Iron deficiency anemia during pregnancy may increase the risk of preterm birth, low birth weight, high blood pressure, and bleeding during labor.

Some types of anemia, like vitamin B12 or pernicious anemia, may damage nerves. This could cause symptoms like numbness in the hands and feet, coordination and balance problems, and memory challenges. If left untreated for a long time, these problems may become permanent and resemble symptoms of dementia.

Iron deficiency anemia has also been linked to mood symptoms, including depression and brain fog, especially for pregnant or postpartum people.

Hemolytic anemia means your red blood cells break down too quickly, which may lead to complications like yellowing of the skin and eyes, and an enlarged spleen.

Long-term hemolytic anemia may lead to pulmonary hypertension, a serious form of high blood pressure in the lungs that causes chest pain and shortness of breath.

Constant red blood cell breakdown may also increase the risk of pigment gallstones and can overwork your kidneys.

When is anemia a medical emergency?

Anemia caused by sudden, severe blood loss can become a life threatening situation. It may lead to hypovolemic shock, which is when your body doesn’t have enough blood flowing to support organ function.

This is a medical emergency that requires urgent care to prevent permanent organ damage or death.

If left untreated, anemia may disrupt nearly every organ of the body.

The complications of anemia are serious, ranging from heart strain to persistent infections to neurological damage. Most of these risks can be prevented with timely medical intervention.

A primary health professional or a hematologist can help with a diagnosis and treatment plan.