Sudden Infant Death Syndrome (SIDS) is the sudden and unexpected death of a baby under the age of 1, usually during sleep, and for which there is no obvious cause, even after a post-mortem. It used to be known as cot death.


How common is SIDS?

About 300 babies die suddenly and unexpectedly every year. That's only about 0.03% of babies born each year in the UK, so SIDS cases are rare. But, while the chances of your baby dying from it are very low, it is worth knowing that SIDS is the most common cause of death in babies under the age of 1.

A baby is likely to be more at risk of SIDS if:

  • he or she was born prematurely
  • his or her birthweight was below average
  • he is a boy

Most SIDS deaths happen in the first 6 months of life, with cases peaking among babies between 2 and 4 months old.

What causes SIDS? How can I prevent it happening to my baby?

No one really know exactly what causes SIDS but experts it affects babies who are vulnerable to certain environmental stresses, such as tobacco smoke, getting tangled in bedding or a minor illness. 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.

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We know how scary all of this sounds.

But, while scientists are still struggling to identify the exact causes SIDS, there have been many years of research to help us identify practical steps every parent can take to significantly reduce their baby's risk of dying of SIDS.

Most of these steps are simple and are focused on making sure that, when you put your baby down to sleep, night or day, you follow these Safe sleep rules for newborns and babies under 6 months.

These little adjustments to the way you baby sleeps can make a huge difference – since a campaign launched in 1991 to put a baby on his or her back to sleep (one of the most important safe sleep rules), there has been a 70% drop in SIDS deaths in the UK.

Why is called SIDS now, instead of cot death?

SIDS used to be referred to (and sometimes still is, by many parents) as 'cot death' but it's now widely agreed among medical experts that this term is misleading.

Why? Because the words 'cot death' imply that the baby can only die in this way when they are asleep in their cot. In fact, babies can die from SIDS when they are asleep in their parents' bed, in a baby sling, or on a sofa or armchair.

What is SUID? Is it the same as SIDS?

SUID is short for Sudden and Unexpected Infant Death, and is a term used, more widely in the US, to describe all unexpected baby deaths, including a SIDS death. After a post-mortem examination and an investigation into the circumstances surrounding the death, an explanation may be found, such as a severe infection or an unsuspected genetic disorder. If no explanation is found, the case is then recorded as a SIDS death.


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Tara BreathnachContent Editor and Social Media Producer

Tara is mum to 1 daughter, Bodhi Rae, and has worked as Content Editor and Social Media Producer at MadeForMums since 2015