Sudden Infant Death Syndrome

Sudden Infant Death Syndrome (SIDS) is when a baby that seems healthy dies suddenly in their sleep, and the cause of death cannot be explained.

SIDS can happen at any time during the first year of life but the risk is highest when babies are 2 to 4 months old.

We do not know what causes SIDS, so it cannot be prevented. But there are things you can do to help lower the risk.

  • Always place your baby on their back to sleep, for every sleep.
  • Provide a smoke free environment before and after birth
  • Breastfeed your baby.
  • Give your baby a safe sleep space that has:
    • a firm, flat surface with a tightly fitted sheet
    • no gaps between the mattress and sides
    • no loose, soft bedding, bumper pads, pillows or toys.
  • The safest place for your baby to sleep is in a crib, cradle or bassinet.
  • Room share: Place your baby to sleep in a crib, cradle or bassinet in the same room as you sleep for the first 6 months.
  • Make sure your baby does not overheat. Your baby is safest when they sleep in simple, fitted sleepwear that keeps them comfortable at room temperature.

Infant deaths can also happen during sleep time when babies accidentally suffocate because of their sleep space. Unlike SIDS, these deaths can be prevented. Most of the safe sleep steps above and in the links below will help decrease your baby's risk of both types of sleep-related deaths.

Fast facts

In the early 2000s, the rate of SIDS in Canada dropped by half, mainly because most parents began placing their babies on their backs to sleep. Lower rates of smoking and higher rates of breastfeeding also helped to lower the SIDS rate.

Since 2012, the term SIDS is not being used to classify infant deaths in most provinces and territories. The term "undetermined" cause is used instead. For more information, see the Joint Statement on Safe Sleep.

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