SIDS (sudden infant death syndrome), also known as crib death, is the unexplained death of a child under the age of 1 year. It usually occurs when an otherwise healthy infant fails to awaken from sleep.

There is no known cause of SIDS. It occurs most often in infants between the ages of 2 months and 4 months. Approximately 2,500 infants die each year of SIDS, according to the American Academy of Family Physicians. SIDS is the leading cause of death among infants between 1 month and 1 year old.

SIDS is diagnosed only after other possible causes of death have been ruled out (e.g., accidents, abuse, undiagnosed medical problems). An autopsy, death scene investigation and evaluation of the child’s health status and medical history are conducted before a diagnosis is made.

Several factors appear to increase the risk of SIDS. Male babies, premature infants and those of American Indian or African American heritage tend to have higher rates of SIDS. Modifiable risk factors include avoiding placing babies to sleep on their stomach, and preventing prenatal and postnatal exposure to cigarette smoke and overheating.