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Sudden infant death syndrome (SIDS)

6-minute read

What are SIDS and SUDI?

Sudden infant death syndrome (SIDS) is the sudden, unexpected and unexplained death of an apparently well baby. It is one of the main causes of Sudden Unexpected Death in Infancy (SUDI), which is the sudden and unexpected death of a baby.

Sometimes babies die from a serious illness or a problem that baby may have been born with. Sometimes it is because of a fatal sleep accident, for example, if they suffocate or get trapped or strangled. When no cause for the death can be found, it is called ‘SIDS’.

SIDS and SUDI are rare and the risk of your baby dying from it is very low. The rate of SIDS deaths has declined in Australia due to safe sleeping campaigns. In 2017, 6 babies in every 100,000 died of SIDS.

Most deaths happen during the first 3 months of a baby’s life. Infants born prematurely or with a low birth weight are at greater risk, and SIDS is also more common in baby boys. Most unexpected deaths occur while the child is asleep in their cot at night.

However, SIDS can also occur when a baby is asleep during the day or, occasionally, while they are awake. Mothers can reduce the risk of SIDS by not smoking while pregnant or after the baby is born, and always placing the baby on their back when they sleep.

What causes SUDI, including SIDS and fatal sleep accidents?

Sudden and unexpected deaths in babies as a result of a medical problem are probably not preventable. However, scientists have identified similar risk factors that are present in SIDS, SUDI and fatal sleep accidents. By removing known risk factors and providing a safe sleeping environment, most of these deaths are preventable.

Experts believe SIDS occurs at a particular stage in a baby’s development, and that it affects babies who are vulnerable to certain environmental stresses such as tobacco smoke, getting tangled in bedding, minor illness or having a breathing obstruction.

Babies who die of SIDS are thought to have problems in the way they respond to these stresses and how they regulate their heart rate, breathing and temperature. Although the cause of SIDS is not fully understood, you can reduce the risk.

What can I do to help reduce the risk of SUDI, including SIDS and fatal sleep accidents?

Sleep baby on their back

Place your baby on their back to sleep from the very beginning, for both day and night sleeps. This will reduce the risk of SUDI. It’s not as safe for babies to sleep on their sides as on their backs. Healthy babies placed on their backs are not more likely to choke.

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

Keep head and face uncovered

Your baby’s blanket should be tucked in no higher than their shoulders. Put your baby’s feet at the bottom of the cot so they can’t slip down under the bedding. You may use a safe baby sleeping bag with fitted neck and arm holes and no hood rather than a blanket.

Keep your baby’s head uncovered when indoors or in a car. That includes no head coverings like bonnets, beanies, hats or hooded clothing.

Keep 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 mothers who smoke during pregnancy and after the birth and also to those smoking around the baby.

If you smoke during pregnancy, your baby is much more likely to die from SUDI than if you don’t.

If your baby is exposed to a smoky environment after they are born, they are much more likely to die from SUDI compared to an infant living in a smoke-free environment. If you smoke, your doctor can recommend appropriate treatment and local support services to help you quit.

Don’t let anyone smoke in the same room as your baby. Anyone who needs to smoke should go outside. Don’t take your baby into smoky places.

Provide a safe sleep environment night and day

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 the mattress and the cot sides. You should remove pillows, doonas, loose bedding, bumpers and soft toys from the cot.

Sharing a sleeping surface with a baby increases the risk of SUDI in some circumstances. Babies who are most at risk are those less than 4 months old, premature babies, and those who are small for gestational age (low birth weight). Avoid falling asleep with your baby on a sofa or an armchair.

Sleep baby in a safe cot in parents' room

The safest place for your baby to sleep is in a cot in a room with you for the first 6 to 12 months. If you smoke, don’t share the same sleep surface with your baby and make sure the bedroom is smoke free.

You should not share a sleep surface with your baby if you have had alcohol or drugs, you are very tired, or the baby could get trapped next to the wall or covered by adult bedding. Make sure there are no other children or pets in the bed.

Breastfeed baby

There is very good evidence that breastfeeding babies can protect them against SUDI.

Checklist for safe sleeping

Red Nose has compiled the following checklist for safe sleeping:

  • Has baby been placed on his or her back to sleep?
  • Is baby sleeping in a safe bassinette or cot, and away from hazards?
  • Does the cot meet the Australian Standard for cots?
  • Is the mattress firm?
  • Does the mattress fit the cot or bassinette well?
  • Is the mattress clean and in good condition and flat (not tilted or elevated)?
  • Is baby’s face and head uncovered?
  • Have any pillows, duvets, lambs wool, cot bumpers and soft toys been removed?
  • If using a baby sleeping bag, does it have a fitted neck, armholes or sleeves and no hood?
  • If using blankets rather than a sleeping bag, has baby been placed to sleep with feet touching the bottom of the cot/bassinette with blankets securely tucked in?
  • Is baby having tummy time to play when awake and supervised?
  • If you are a smoker have you stopped smoking or contacted your doctor or Quitline for help?
  • Remember never to sleep baby on a sofa, bean bag, waterbed or pillow.
  • Are other family members aware of how to sleep baby safely?

Read more about safe sleep for your baby.

For more information on SIDS and safe sleeping, please visit Red Nose at www.rednose.com.au.

Minimising the risk of SIDS - video

Video provided by Raising Children Network.

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

Last reviewed: July 2020


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