Sudden infant death syndrome (SIDS) is the sudden, unexplained death of an infant younger than one year old. Some people call SIDS "crib death" because many babies who die of SIDS are found in their cribs.

SIDS is the leading cause of death in children between one month and one year old. Most SIDS deaths occur when babies are between two months and four months old. Premature babies, boys, African Americans, and American Indian/Alaska Native infants have a higher risk of SIDS.

Although health care professionals don't know what causes SIDS, they do know ways to reduce the risk. These include

• Placing babies on their backs to sleep, even for short naps. "Tummy time" is for when babies are awake and someone is watching
• Using a firm sleep surface, such as a crib mattress covered with a fitted sheet
• Keeping soft objects and loose bedding away from sleep area
• Making sure babies don't get too hot. Keep the room at a comfortable temperature for an adult.
• Don't smoke during pregnancy or allow anyone to smoke near your baby

NIH: National Institute of Child Health and Human Development