Sudden infant death syndrome, commonly called SIDS, is a label used to describe unexplained infant death. An infant’s death may be labeled as a SIDS death when it occurs suddenly and unexpectedly and it cannot be explained. This label is only applied after an infant’s death has been thoroughly investigated. SIDS is the leading cause of death in healthy infants between one month and 12 months old. Although the cause of SIDS death is not understood, some factors have been shown to reduce the risk.