SIDS is the sudden, unexplained death of an infant younger than 1 year of age that remains unexplained after a complete investigation. This investigation can include an autopsy, a review of the death scene, and complete family and medical histories.1
A diagnosis of SIDS is made by collecting information, conducting scientific or forensic tests, and talking with parents, other caregivers, and health care providers. If, after this process is complete, there is still no identifiable cause of death, the infant's death might be labeled as SIDS.