Sudden unexpected infant deaths are defined as deaths in infants less than 1 year of age that occur suddenly and unexpectedly, and whose cause of death are not immediately obvious prior to investigation.
Each year in the United States, about 4,000 infants die suddenly of no immediately, obvious cause. About half of these Sudden Unexpected Infant Deaths (SUID) are due to Sudden Infant Death Syndrome (SIDS) the leading cause of SUID and all deaths amont infants aged 1-12 months.
The three most frequently reported causes are SIDS, cause unknown, and accidental suffocation and strangulation in bed. In 2010, 2,063 deaths were reported as SIDS, 918 as cause unknown, and 629 as accidental suffocation and strangulation in bed.