SIDS (sudden infant death syndrome), also known as crib death, is the unexplained and abrupt death of a baby 1 year old or younger. SIDS usually occurs among otherwise healthy infants, and is associated with sleep. In most cases, a sleeping baby simply never wakes up.

SIDS is a leading cause of death in infants. Approximately 2,500 babies die each year of SIDS, according to the American Academy of Family Physicians. Those who have died of SIDS show no signs of suffering. Most cases of SIDS involve infants between 2 months and 4 months old. The majority of cases occur at home, but some occur in childcare settings.