By Raising Children Network
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Sudden Infant Death Syndrome (SIDS) is the term used when a baby dies unexpectedly and for no obvious reason. These deaths are devastating but can’t be predicted. You can, however, take precautions against SIDS.


There has been an enormous amount of research into SIDS, but we still don’t know exactly what causes it.

SIDS probably has several different causes, one or more of which might be responsible for a particular baby’s death. It’s widely believed that being around people who smoke increases a baby’s risk of SIDS.

Contributing factors
SIDS is generally more common in winter, in colder climates, in families from lower socioeconomic groups, and in babies who have been born very prematurely. It usually happens between the ages of 1-6 months, and is rare after children turn one.

The onset of the fatal episode in SIDS is thought to occur during sleep. There’s usually no sign that anything was wrong with the baby, and no sign during the night that the baby was upset or unwell. Sometimes the baby might have had a very mild cold in the days before the death.

SIDS affects about 1 in every 3000 infants. SIDS deaths have fallen significantly in the past few years all around the world.


There are no specific symptoms of SIDS before the death or afterwards.

In about half of cases, parents say their baby had a mild cold (for example, a sniffly or runny nose, or mild fever) in the days before death. But mostly the cold was so mild that parents didn’t go to the doctor. Some went to the doctor and were told their baby was well.

The impact

Parents, and other family members, are understandably devastated by SIDS. They feel anger, guilt, frustration and, above all, grief.

Parents will go over every moment in the last few hours or days of their child’s life, searching for clues. They might wonder whether their baby might still be alive if they’d done things a little differently. They might feel guilty they didn’t check on their baby one last time before going to sleep themselves, or that the cot wasn’t in their room, or that they didn’t wake the baby for a midnight feed. If you’ve been affected by SIDS, it’s completely normal to have these feelings.

You can’t do anything to predict the death of a baby from SIDS. Apart from following the guidelines for preventing SIDS outlined below, there’s nothing parents can do that could have prevented their baby’s death.

SIDS and Kids counsels bereaved families around Australia, as well as funding SIDS research and doing community education about SIDS. When a child dies from SIDS, it can affect not only parents, but also brothers, sisters, grandparents and their family members and friends. Talking with trained counsellors from SIDS and Kids really can help.


Although we don’t know what causes SIDS, research over recent years has shown some strong links between SIDS and several risk factors. Paying attention to these risk factors might reduce the risk of SIDS. In fact, the publicity that these risk factors have received has helped reduce cases of SIDS all around the world.

Sleeping position
There’s now very strong evidence that babies put to sleep on their stomach are at increased risk for SIDS. Always put your baby to sleep on his back.

Sleeping environment
It’s recommended that your baby sleep in her own cot next to your bed for the first 6-12 months of her life. Put your baby in the cot with her feet at the bottom of the cot, so that she can’t move down in her sleep. This will stop her face getting covered with blankets.

Never sleep on a sofa with your baby. Never sleep in the same bed as your baby if you’ve been drinking alcohol or taking drugs.

Keep your baby cool
Your baby will get too hot if he’s covered with too many blankets. If your baby has a cold or a fever, he needs even fewer blankets. Don’t put soft pillows, cushions and bumpers in the cot because they restrict the flow of fresh air around your baby’s head, and might increase the temperature. Make sure the room isn’t overheated.

Wrap your baby so her head and arms move freely. Avoid putting hats or bonnets on her while she’s sleeping, because head coverings increase body temperature.

Smoke-free environment
Smoking increases the risk of SIDS. The best thing to do is to not smoke during pregnancy (smoking also causes other problems for your unborn baby). If you’re a smoker, keep your baby in a smoke-free environment. Don’t smoke in the same room as your baby, and ask others not to smoke near him. If you do smoke, sharing a bed with your baby increases the risk of SIDS.

Avoid stuffed toys in the cot
Comforters, fluffy blankets and stuffed toys in the cot can increase your baby’s temperature or lead to suffocation.

You might like to print out our illustrated guide to reducing the risk of SIDS. You can pin it up somewhere in your home. You could also give it to anyone who cares for your baby.

Apparent life-threatening episodes (ALTE)

A number of babies have these episodes, which in the past have sometimes been called ‘near miss SIDS’. An ALTE is where the baby is found limp, sometimes blue, sometimes unconscious or unresponsive, and not breathing. Different amounts of stimulation are needed to revive babies in this condition, ranging from noise or gentle movement of a limb to CPR. This is terrifying for parents, and these babies are usually then admitted to hospital for close monitoring and investigation.

The causes of these episodes are varied and include:

  • convulsions (fits)
  • choking, sometimes caused by food coming up from the stomach and going down the wrong way (gastro-oesophageal reflux)
  • the heart losing its rhythm (cardiac arrhythmias)
  • the baby ‘forgetting’ to breathe (apnoeic episodes) – this is usually caused by an immature central nervous system, but might also be caused by certain viruses, such as respiratory syncytial virus.

There is often no cause found for an ALTE.

The relationship between ALTEs and later SIDS isn’t clear, although up to 13% of infants who die from SIDS have had an ALTE. If a cause for the ALTE is found, it’s treated. If no cause is found, parents are assured it’s unlikely to happen again.

Sometimes an apnoea alarm is used to monitor the baby’s breathing. Apnoea alarms aren’t totally reliable and can cause great anxiety in parents, who often say they lie awake at night waiting for the alarm to go off. There’s no evidence to show that an apnoea alarm reduces the incidence of SIDS.

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  • Last Reviewed 19-05-2011
  • Frederico, M.J.,Kerby, G.S., Deterding, R.R., Baker, C.D., Balasubramaniam, V., Zemanick, E.T., Sagel, S.D., Cavanagh, K.L., & Accurso, F.J. Burch. (2009). Respiratory tract and mediastinum. In W. Hay, M. Levin, J. Sondheimer & R. Deterding (Eds), Current diagnosis and treatment: Pediatrics. (20th edn, pp. 487-535). New York: McGraw-Hill. 

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