Down syndrome factsheet


Down syndrome is a genetic condition where a baby is born with three copies of the 21st chromosome instead of two. It is also called trisomy 21. 

Chromosomes are structures that carry information about a person. The extra copy of chromosome 21 changes a baby's body and brain development. 

Down syndrome happens randomly. It is not known what causes the chromosome to make a third copy. The chance of Down syndrome being passed on from parent to child is 1%. 

 Signs and symptoms

Children with Down syndrome have some shared physical features, including: 

  • the shape of their eyes, nose and throat
  • a rounded face
  • shorter height.

They will also have intellectual disability and developmental delays. This means they will need extra support to learn as they grow.

Children with Down syndrome are more at risk of some health issues, including:


Down syndrome is usually diagnosed during pregnancy, but it can also be diagnosed when a baby is born.

Screening tests that estimate the chance of different conditions can be done during pregnancy. These tests can only give an estimate and do not confirm that a baby will be born with a condition. 

Screening tests include:

  • first trimester combined screening test:  results from blood tests taken at 10-12 weeks of pregnancy are compared with scan results taken at 11-13 weeks of pregnancy
  • maternal serum screening: a blood test taken at 15-20 weeks of pregnancy
  • non-invasive prenatal test (NIPT): a blood test taken after 10 weeks of pregnancy.

Diagnostic tests will be offered if the results show there is a chance of your baby having Down syndrome.

Diagnostic tests confirm a condition. They include::

  • chorionic villus sampling (CVS):  a small sample of tissue is taken from the placenta between 11-12 weeks of pregnancy for testing
  • amniocentesis: a sample of the amniotic fluid, the fluid surrounding the baby, is collected by a needle for testing. 

    Note: Amniocentesis has a 1 in 200 risk of miscarriage.

Ultrasounds and blood tests are a normal part of pregnancy care. Screening and diagnostic tests that look for conditions like Down syndrome are optional.

When a baby is born, the doctor or midwife may check your baby for Down syndrome based on how their face looks. This is because people with Down syndrome can have a unique face, eyes, and nose shape. 

A blood test will be done to confirm whether your baby has Down syndrome or not.


Down syndrome cannot be cured or prevented. It is a genetic condition that happens randomly.

People with Down syndrome will have some level of intellectual disability and developmental delay, and are more at risk of health problems. 

Treatment focuses on:

  • checking for and treating physical health problems
  • supporting your child's learning and development
  • supporting your child to be an active member of the community
  • supporting your child to live an independent life, where possible.

Every person with Down syndrome is unique, just like everyone else. The level of support needed will be different for every child and may change throughout their life.


Heart disease and defects

Around 50% of people with Down syndrome are born with heart disease or defects. A heart defect is a difference in how your child's heart has grown.

Babies diagnosed with Down syndrome during pregnancy will have extra scans between 18-20 weeks of pregnancy to check for any issues with their heart. 

Newborn babies with Down syndrome will be checked by a heart specialist called a cardiologist.

Hearing loss

Children with Down syndrome are more at risk of being born with or developing hearing loss.

Because people with Down syndrome can have unique face shapes, there can be differences in the shape of their ears, nose, and throat.

These differences mean children with Down syndrome have a higher risk of:

  • trapped fluid in the ear, or glue ear
  • build-up of ear wax
  • ongoing middle ear infections
  • constant nasal and sinus infections.

Hearing loss that develops because of these conditions is called conductive hearing loss. Conductive hearing loss needs to be treated quickly to avoid issues with learning and development.

Children with Down syndrome are also at risk of permanent or sensorineural hearing loss. This type of hearing loss is caused by damage to the inner ear. Some children are born with this hearing loss, while others develop it as they get older.

Some children with Down syndrome have a mix of conductive and sensorineural hearing loss.

The NSW State-wide Infant Screening - Hearing (SWISH) test is used to find hearing loss in newborn babies. Hearing loss can also be found using different scans and behavioural tests done by a hearing specialist called an audiologist.
Your child will have a treatment team who will help treat and manage any hearing loss. 

The treatment team can include:

  • audiologist – an allied health specialist who looks after hearing
  • speech pathologist - an allied health specialist who looks after language and communication
  • paediatrician – a specialist children's health doctor
  • ear, nose, and throat specialist
  • your local doctor.

Support for learning and development

Children with Down syndrome also have intellectual disability and developmental delays. This means they will need more support and resources to learn and develop new skills at their own pace. 

Your child may be able to access extra support at school and home to help them with learning and development. Talk to your doctor about early intervention services and support through the National Disability Insurance Scheme (NDIS).

Early intervention will help your child in four main areas of development:

  • physical development – building strength and movement skills
  • cognitive development – communicating, thinking and learning
  • behavioural development – managing behaviours that are affected by physical and cognitive development
  • social and emotional development – learning social skills, forming relationships, and managing emotions.

Support for your family

Families are very important in supporting children with Down syndrome to learn and develop skills and become part of the community. 

Children with Down syndrome may need more medical and therapy appointments, which can cause stress for parents and carers. 

There is support available for families through Down syndrome Australia. They can connect you with information and support in your area, including:

  • counselling and support in-person or via phone
  • NDIS funding and services
  • connecting you with the community and other families with Down syndrome.

Resources and more information

Down Syndrome Australia

Down Syndrome Australia

Email Send email
Phone1300 881 935
The Down Syndrome Federation provides a range of supports and services for people with Down syndrome, their families and supporters.
Related Links
The National Disability Insurance Scheme (NDIS)

The National Disability Insurance Scheme (NDIS)

Email Send email
Phone1800 800 110
The National Disability Insurance Scheme (NDIS) supports people with a permanent and significant disability that affects their ability to take part in everyday activities.
Related Links
Carers NSW Australia

Carers NSW

Email Send email
Phone(02) 9280 4744
Provides information, education and training, resources and referrals to support carers.
Related Links
Australian Government - Carer Gateway

Carer Gateway

Phone1800 422 737
A national service that provides practical information about services and support available to carers.
Related Links
Parent Line NSW

Parent Line NSW

Phone1300 130 052
A free telephone counselling and support service for parents and carers with children aged 0 to 18 who live in NSW.
Related Links
Relationships Australia - New South Wales

Relationships Australia NSW

Phone1300 364 277
Relationship support services including counselling for individuals, couples and families as well as parenting and relationship education.
Related Links
Siblings Australia Inc. - for siblings of children and adults with disability/illness

Siblings Australia

Email Send email
Phone(08) 8253 4936
Support for siblings of children and adults with chronic conditions including disability, chronic illness and mental health issues.
Related Links
Last updated Tuesday 20th February 2024


This factsheet is provided for general information only. It does not constitute health advice and should not be used to diagnose or treat any health condition.

Please consult with your doctor or other health professional to make sure this information is right for you and/or your child.

The Sydney Children’s Hospitals Network does not accept responsibility for inaccuracies or omissions, the interpretation of the information, or for success or appropriateness of any treatment described in the factsheet.

© Sydney Children’s Hospitals Network 2024