Sudden infant death syndrome (SIDS) is the death of a baby who is
younger than 1 year old without a known cause. Typically, a parent or other
caregiver puts the baby—who seems healthy—down to sleep and returns later to
find the baby has died.
No one is at fault when a baby dies of SIDS: it can be neither
predicted nor completely prevented. A baby's death is not considered a case of
SIDS when a specific cause is discovered, such as carbon monoxide poisoning. By
definition, SIDS is considered the cause of a baby's death only when the death
remains unexplained, even after a thorough investigation.
SIDS is also known as sudden unexpected infant death (SUID).
Placing babies on their backs when putting them down to sleep
reduces the risk of SIDS.