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Sudden infant death syndrome (SIDS)

8-minute read

Key Facts

You can reduce the risk of SIDS by:

  • always placing your baby on their back when they sleep
  • make sure your baby’s face is not covered when they are sleeping
  • keeping your baby away from cigarette smoke before and after birth
  • providing a safe sleeping environment
  • sleeping your baby in their own cot
  • having your baby’s cot in your room for their first 6 to 12 months of life

What is sudden unexpected death in infancy (SUDI)?

Sudden unexpected death in infancy (SUDI) is a term used to describe the sudden and unexpected death of a baby that is less than 12 months old. It is used when the cause is not immediately obvious.

Investigations after death can explain some deaths. These may be due to:

  • accidental death
  • smothering by bedclothes
  • infection
  • metabolic disorders
  • genetic disorders
  • non-accidental injury

Sometimes these deaths happen because a baby has suffocated or been trapped by things in their sleep environment. This is called a fatal sleeping accident. When no cause for the death can be found, it is called sudden infant death syndrome (SIDS).

What is sudden infant death syndrome (SIDS)?

SIDS is the name given to the unexpected death of a baby when the cause is unknown. It was previously called cot death.

SIDS causes more deaths of babies aged between one month and one year than any other cause.

SIDS is one of the main causes of Sudden Unexpected Death in Infancy (SUDI).

How often does SIDS occur?

SUDI and SIDS are rare and the risk of your baby dying from these is very low. The rate of SIDS deaths has declined in Australia due to safe sleeping campaigns. In 2020, 100 babies in Australia died of SUDI (data from Queensland, New South Wales, Victoria and Western Australia only).

What causes SIDS?

The causes of SIDS are still not known. Researchers think that SIDS is caused by a number of factors. These are divided into 3 groups:However, there are things you can do to reduce the risk of SUDI.

Can SUDI be prevented?

Scientists have found 6 risk factors that are associated with SUDI. By removing these risk factors you can reduce the chance of SUDI.

  1. Sleep your baby on their back.
  2. Keep your baby’s head and face uncovered.
  3. Keep your baby’s environment smoke free, before and after birth.
  4. Make sure they have a safe sleeping environment.
  5. Sleep your baby in a cot, in your room.
  6. Breastfeed your baby, if you can.

Sudden and unexpected deaths that happen because of an unknown medical problem are not preventable.

1. Sleep your baby on their back

Place your baby on their back to sleep. You should do this from the very beginning, for both day and night sleeps. This will lower the risk of SUDI.

Healthy babies put on their backs are less likely to choke on vomit.

Only sleep your baby on their side if your doctor tells you to do this.

When your baby is old enough to roll over, don’t stop them from doing so.

I’m concerned my baby will get a flat head

Flat head can happen if your baby lies in one position for long periods of time.

There are a few things you can do to stop flat head developing:

  • change your baby’s head position (left or right) when you put them in their cot
  • don’t leave your baby seated for long periods
  • offer increasing amounts of tummy time when your baby is awake

To help change your baby’s head position you can:

  • place your baby at different ends of their cot
  • change their cot position
  • put toys or mobiles in different places to attract their attention

2. Keep your baby’s head and face uncovered

Ensure that your baby’s face and head is not covered when they are sleeping.

You may use a baby sleeping bag with fitted neck and arm holes rather than a blanket.

If you use blankets, they should be tucked in tightly. They should also be no higher than your baby’s shoulders. Put your baby’s feet at the bottom of the cot so they can’t slip down under the bedding.

Keep your baby’s head uncovered when indoors or in a car. That includes no head coverings like hats or hoods.

3. Keep your baby smoke free before and after birth

Exposure to cigarette smoke can significantly increase your baby’s risk of dying suddenly and unexpectedly. This applies to smoking both during pregnancy and after they are born.

The risks of SUDI are also higher if your baby sleeps with a parent who is a smoker.

Your doctor can support you to quit smoking. Or you can call the Quitline on 13 QUIT (13 7848).

Don’t let anyone smoke in the same room as your baby. Anyone who wants to smoke should smoke outside . They should change their clothes before holding your baby. Don’t take your baby into smoky places.

4. Provide a safe sleep environment for your baby

Make sure the cot, mattress and bedding are safe and meet Australian standards.

The mattress should be firm, flat and clean. Make sure your baby can’t get wedged between their mattress and the cot sides.

Remove these items from your baby’s cot:

  • pillows
  • fluffy toys
  • quilts or doonas
  • bumpers

5. Sleep your baby in a cot in your room

The safest place for your baby to sleep is in a cot in a room with you. This should ideally happen for their first 6 to 12 months. It’s thought that increased supervision and observation of your baby is protective against SUDI.

Sharing the same room during your baby’s daytime sleeps is also protective. A bassinette or portable cot can be used for daytime sleeps.

Is it safe to sleep with my baby?

You may choose to share a sleep surface with your baby due to parenting preferences, cultural beliefs or living circumstances.

The risk of SUDI isn’t increased if you feed, cuddle or play with your baby in your bed. You should put your baby back in their cot before going to sleep.

Co-sleeping can increase the risk of SUDI. The risk is greater if you:

  • have used alcohol
  • have used drugs
  • are very tired
  • Never sleep your baby on a: sofa, bean bag, waterbed or pillow. There is a high risk of SUDI when a baby shares a sofa or couch with an adult during sleep.

6. Breastfeed your baby

There is very good evidence that breastfeeding your baby can help protect them against SUDI.

The protective effect of breastfeeding is stronger the longer you exclusively breastfeed.

If you can’t breastfeed you can reduce the risk of SUDI using the other five safe sleep strategies.

SUDI in Aboriginal and Torres Strait Islander infants

There is a large gap in infant and child mortality between Aboriginal and Torres Strait Islander people and non-Indigenous Australians.

SUDI has been reported as a predominant cause of Aboriginal and Torres Strait Islander infant death. SIDS accounted for one in 20 deaths among all Aboriginal and Torres Strait Islander infants in 2011 to 2015.

The key risk factors associated with SUDI in Aboriginal and Torres Strait Islander infants are:

  • low birthweight
  • premature birth
  • maternal nutrition during pregnancy
  • maternal smoking
  • maternal alcohol use
  • lack of regular antenatal care

Keeping Bub Safe is a booklet produced by Red Nose to reduce the risk of SIDS in Aboriginal Communities.

Minimising the risk of SIDS - video

Make sure that your friends and family members know how to sleep your baby safely.

Video provided by Raising Children Network.

Resources and support

You can read more about safe sleep for your baby.

To find out more about SIDS and safe sleeping, please visit Red Nose.

Red Nose also offers support to anyone affected by SUDI. For more information call the Red Nose Grief and Loss Support Line on 1300 308 307 or visit

Speak to a maternal child health nurse

Call Pregnancy, Birth and Baby to speak to a maternal child health nurse on 1800 882 436 or video call. Available 7am to midnight (AET), 7 days a week.

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: December 2022

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