Complications of Down's syndrome 

Some children with Down's syndrome have very few health problems as a result of their condition. Others will experience several of the more common health conditions and will need extra medical care and attention.

Possible health complications of Down's syndrome include:

  • heart disorders
  • bowel abnormalities
  • digestive problems
  • hearing and vision impairments
  • thyroid dysfunctions
  • increased risk of infections
  • blood disorders
  • increased risk of dementia

These are outlined in more detail below.

While some of these conditions are serious, most are not. Your child may be checked by a paediatrician more often than other children to pick up developing problems as early as possible. If you have any concerns about your child's health, discuss them with your GP, health visitor or paediatrician.

Heart disorders

Around 50% of children with Down's syndrome have a congenital heart defect. A congenital defect means that you are born with it. Around 60% of children with Down's syndrome who are born with a heart defect require treatment in hospital. 

Septal defects account for 9 out of 10 cases of congenital heart disease in people with Down's syndrome. A septal defect is a hole inside one of the walls that separate the four chambers of the heart, often referred to as a "hole in the heart". 

It can cause a build-up of blood in one or more of the heart's chambers, which causes the heart to work harder to pump blood through the four chambers.

Less common but serious types of congenital heart disease in people with Down's syndrome include:

  • tetralogy of Fallot, which accounts for 6% of cases
  • patent ductus arteriosus, which accounts for around 4% of cases

Tetralogy of Fallot is a combination of four different heart defects that causes a lowering of oxygen levels in the blood. This can lead to symptoms of breathlessness.

Patent ductus arteriosus (PDA) is a duct or passage in the heart that usually closes shortly after birth. However, in cases of PDA the duct fails to completely close, which means oxygen-rich blood that is meant to be pumped away from the lungs leaks back through the duct and into the lungs.

This can place strain on the heart and lungs because they have to work harder to compensate for the problems caused by the duct.

If your baby is diagnosed with Down's syndrome, their heart will be carefully assessed to detect and treat any problems as soon as possible.

Intestinal problems

Many people with Down's syndrome have some sort of intestinal problem. Constipationdiarrhoea and indigestion are all common, as are more serious problems such as small bowel obstruction, which stops food passing from the stomach into the large bowel.

An estimated 5-15% of people with Down's syndrome develop coeliac disease (an intolerance to gluten).

Conditions such as imperforate anus (where a baby is born without an anal opening) or Hirschsprung's disease (where the large bowel is unable to push faeces towards the anus) are rare, but slightly more common in children with Down's syndrome.

Hearing problems

Around 50% of people with Down's syndrome have problems with their ears and hearing.

Glue ear commonly affects people with the condition. It is caused by a build-up of fluid in the middle ear. In some cases, the fluid thickens and causes sounds to be muffled and distorted.

If your child has a hearing problem, they may find it difficult to learn and interact with other children. If your child has glue ear as a result of Down's syndrome, they will usually be referred to an ear, nose and throat (ENT) specialist for treatment.

Vision problems

Around 50% of people with Down's syndrome also have problems with their eyesight.

Common eye problems include:

  • squint 
  • lazy eye – where one eye does not develop fully and loses some focusing ability
  • short-sightedness – where distant objects appear blurred
  • long-sightedness – where nearby objects appear blurred
  • eye infections (conjunctivitisuveitis or blepharitis)
  • cataracts – where the lens (the transparent layer at the front of the eye) clouds over
  • nystagmus – where the eyes move uncontrollably, usually from side to side
  • keratoconus – where the cornea becomes thin and bulges out

Thyroid problems

Around 10% of people with Down's syndrome have problems with their thyroid gland. The thyroid gland is located in the neck and is responsible for controlling your metabolism (the rate at which your body uses up energy). It does this by releasing thyroid hormones into the body.

Most people with Down's syndrome who have a problem with their thyroid have hypothyroidism, which means their thyroid gland is underactive. Symptoms of an underactive thyroid gland can include:

  • lethargy (lack of energy)
  • weight gain
  • slow physical and mental reactions

In rarer cases, people with Down's syndrome can also develop hyperthyroidism, which means their thyroid gland is overactive and produces too much thyroid hormone. Symptoms of hyperthyroidism can include:

  • hyperactivity
  • difficulty breathing
  • difficulty sleeping

Increased risk of infection

People with Down's syndrome are more likely to develop infections, particularly the lung infection pneumonia. This is because their immune system (the body's natural defence against infection) has not developed properly.


Children with Down's syndrome also have an increased risk of developing acute leukaemia.

Around 1 in 100 children with Down's syndrome go on to develop acute leukaemia.


Dementia is a frequently voiced concern about people with Down's syndrome. There is a tendency for people with Down's syndrome to develop dementia at a younger age than in the general population.

However, recent research indicates that the overall percentage of adults with Down's syndrome who develop dementia is similar to that of the population who do not have Down's syndrome. It is not inevitable that people with Down's syndrome will develop the condition.

Page last reviewed: 24/01/2013

Next review due: 24/01/2015