Sudden infant death syndrome, or SIDs, is the leading cause of sudden unexpected infant deaths (SUID) in the United States. Although death rates have steadily decreased since 1990, in 2013 about 1,500 infants died from SIDs.
While the cause of SIDs is unknown, it is the leading cause of death among babies between one month and one year of age, with 90 percent of deaths occurring before six months of age. Since 1990, the incidence of sudden infant death syndrome has declined remarkably, from 130.3 deaths per 100,000 live births in 1990, to 39.7 deaths per 100,000 live births in 2013.
SIDs is sometimes called "crib death" because these deaths usually coincide with the times that the infant is sleeping. Scientific research suggests that SIDs is more likely to occur in infants who have three major risk factors. These three risk factors are known as the "triple-risk model," and include: a vulnerable infant (a child born with a brain abnormality or defect), changes during the first six months of life that may destabilize the infant's body temperature and vital signs, and outside stressors such as overheating and the infant sleeping on his stomach. Scientists believe that in order for sudden infant death syndrome to occur, all three elements must be present.