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.


As iron deficiency anaemia can leave you tired and lethargic (lacking in energy), you may be less productive and active at work. Your ability to stay awake and focus could decrease, and you may 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), making you more likely to become ill.

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 (an abnormally fast heartbeat) or heart failure (where your heart is not pumping blood around your body very efficiently).

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 parents 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 birthweight
  • have problems with iron levels themselves
  • do less well in mental ability tests

Restless legs syndrome

Some cases of restless legs syndrome (RLS) are thought to be caused by iron deficiency anaemia. Doctors may refer to this as "secondary RLS".

RLS is a common condition affecting the nervous system, which causes an overwhelming, irresistible urge to move the legs. It also causes an unpleasant feeling in the feet, calves and thighs.

RLS caused by iron-deficiency anaemia can usually be treated with iron supplements.

Page last reviewed: 24/03/2014

Next review due: 24/03/2016