The cause of sudden infant death syndrome (SIDS) is unknown.
However, some studies have found an association between SIDS and certain risk factors. For example, SIDS is more common in babies who:
- are male
- were born with a low birth weight
- were born prematurely
- had a sibling who died of SIDS (although it is still rare for SIDS to occur more than once in the same family)
The following factors can also increase the risk of SIDS.
Tobacco smoke
Exposing your baby to tobacco smoke (both smoking during pregnancy and after your baby is born) can significantly increase the risk of SIDS.
Smoking during pregnancy means that your baby is four times more likely to die from SIDS than if you did not smoke. Continually exposing your baby to a smoky environment after birth means your child will be eight times more likely to die from SIDS than if they lived in a smoke-free environment.
Sleeping
Where and how your baby sleeps can also affect the risk of SIDS. Babies are more at risk of SIDS if they sleep:
- with an adult rather than in their own crib or cot (especially if the adult has consumed alcohol or drugs)
- on their side or stomach
- with a duvet, quilt or pillow
Your baby's temperature is also important. If your baby is too hot, this can increase the risk of SIDS.
For information on how to reduce the risks of SIDS, see SIDS - prevention.
