Anaemia, iron deficiency - Complications of iron deficiency anaemia

Iron deficiency anaemia rarely causes serious or long-term complications, although some people with the condition find it affects their daily life.

Some common complications are outlined below.


Iron deficiency anaemia can make you feel tired and lacking in energy (lethargic). This may result in you being less productive at work, and you may find it difficult to stay awake or not feel able to exercise regularly.

Increased risk of infections

Research has shown iron deficiency anaemia can affect your immune system ‐ the body's natural defence system. This increases your vulnerability to infection.

Heart and lung problems

Adults with severe anaemia may be at risk of developing complications that affect their heart or lungs.

For example, you may develop tachycardia, which is an abnormally fast heartbeat, or heart failure, where the heart fails to pump enough blood around your body at the right pressure.

Pregnancy complications

Pregnant women with severe anaemia have an increased risk of developing complications, particularly during and after birth.

They may also develop postnatal depression, which some women experience after having a baby.

Research suggests babies born to mothers who have untreated anaemia are more likely to:

  • be born prematurely ‐ before the 37th week of pregnancy
  • have a low birth weight
  • have problems with iron levels themselves
  • do less well in mental ability tests

Restless legs syndrome

Some cases of restless legs syndrome are thought to be caused by iron deficiency anaemia. Doctors often refer to this as secondary restless legs syndrome.

Restless legs syndrome is a common condition that affects the nervous system, and causes an overwhelming, irresistible urge to move the legs. It also causes an unpleasant feeling in the feet, calves and thighs.

Restless legs syndrome caused by iron deficiency anaemia can usually be treated with iron supplements.


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