What is Sudden Unexpected Infant Death (SUID)

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, more than 4,500 infants die suddenly of no immediately, obvious cause. Half of these Sudden Unexpected Infant Deaths (SUID) are due to Sudden Infant Death Syndrome (SIDS), the leading cause of SUID and of all deaths among infants aged 1–12 months.

CDC supports new recommendations issued by the American Academy of Pediatrics (AAP). These new recommendations aim to reduce the risk of infant death from SIDS as well as death from known sleep-related causes. Read the AAP fact sheet for more information.

Sudden Infant Death Syndrome (SIDS)
Sudden Infant Death Syndrome (SIDS) is defined as the sudden death of an infant less than 1 year of age that cannot be explained after a thorough investigation is conducted, including a complete autopsy, examination of the death scene, and review of the clinical history.

SIDS is the leading cause of death among infants aged 1–12 months, and is the third leading cause overall of infant mortality in the United States. Although the overall rate of SIDS in the United States has declined by more than 50% since 1990, rates for non-Hispanic black and American Indian/Alaska Native infants remain disproportionately higher than the rest of the population. Reducing the risk of SIDS remains an important public health priority.

For a medical examiner or coroner to determine the cause of the death, a thorough case investigation including examination of the death scene and a review of the infant's clinical history must be conducted. A complete autopsy needs to be performed, ideally using information gathered from the scene investigation. Even when a thorough investigation is conducted, it may be difficult to separate SIDS from other types of sudden unexpected infant deaths, especially accidental suffocation in bed.

After a thorough case investigation, many of these sudden unexpected infant deaths may be explained. Poisoning, metabolic disorders, hyper or hypothermia, neglect and homicide, and suffocation are all explainable causes of SUID.