Common SIDS and SUID Terms And Definitions

Health care providers and others may use some of the following terms when discussing infant deaths.

  • Sudden Unexpected Infant Death (SUID): The death of an infant younger than 1 year of age that occurs suddenly and unexpectedly. After a full investigation, these deaths may be diagnosed as:
    • Suffocation: When no air reaches a baby's lungs, usually caused by a block in the airway
    • Entrapment: When a baby gets trapped between two objects, such as a mattress and wall, and can't breathe
    • Infection: When a baby has a cold or other infection caused by a virus or bacteria that makes breathing difficult
    • Ingestion: When a baby takes something into the mouth that blocks the airway or causes choking
    • Metabolic diseases: Conditions related to how the body functions that can lead to problems with breathing
    • Cardiac arrhythmias: When a baby's heart beats too fast or too slow and affects breathing
    • Trauma (accidental or non-accidental): When a baby experiences an injury
    • SIDS

In some cases, the evidence is not clear or not enough information is available, so the death is considered to be of undetermined cause.

  • Sudden Infant Death Syndrome (SIDS): One type of SUID, SIDS is the sudden death of an infant younger than 1 year of age that cannot be explained even after a full investigation that includes a complete autopsy, examination of the death scene, and review of the clinical history.
  • Accidental Suffocation and Strangulation in Bed (ASSB): One type of SUID, ASSB is a cause-of-death code used for vital statistics purposes. This code is used to identify infant deaths caused by suffocation or asphyxia (blockage of the infant's airway) in a sleeping environment. For example:
    • Suffocation by soft bedding: When soft bedding, a pillow, or a waterbed mattress blocks the infant's airway.
    • Overlay: When another person shares the sleep surface with the infant and lays on or rolls on top of or against the infant while sleeping, blocking the infant's airway.
    • Wedging or entrapment: When an infant gets trapped between two objects, such as a mattress and wall, bed frame, or furniture, blocking the infant's airway.
    • Strangulation: When something presses on or wraps around the infant's head and neck blocking the airway.
  • Co-Sleeping: A sleep arrangement in which the parent (or another person) and infant sleep in close proximity (on the same surface or different surfaces) so as to be able to see, hear, and/or touch each other. Co-sleeping arrangements can include room sharing or bed sharing. The terms "bed sharing" and "co-sleeping" are often used interchangeably, but they have different meanings.
  • Room Sharing: A sleep arrangement in which an infant sleeps in the same room as parents or other adults, but on a separate sleep surface, such as a crib, bassinet, or play yard. The American Academy of Pediatrics (AAP) recommends that the infant's sleep surface be close to the parents' bed to aid in feeding, comforting, and monitoring of the infant. Room sharing is known to reduce the risk of SIDS and other sleep-related causes of infant death.
  • Bed Sharing: A sleep arrangement in which an infant sleeps on the same surface, such as a bed, couch, or chair, with another person. Sleeping with a baby in an adult bed increases the risk of suffocation and other sleep-related causes of infant death.