Sleep-Related Infant Suffocation Deaths Attributable to Soft Bedding, Overlay, and Wedging

Unintentional suffocation is the leading cause of injury death among infants <1 year old in the United States, with 82% being attributable to accidental suffocation and strangulation in bed. Understanding the circumstances surrounding these deaths may inform prevention strategies.

We analyzed data from the population-based Sudden Unexpected Infant Death Case Registry from 2011 to 2014. Cases categorized as explained suffocation with unsafe sleep factors (suffocation), per the Centers for Disease Control and Prevention's Sudden Unexpected Infant Death Case Registry classification system, were included and assigned a mechanism of obstruction, including soft bedding, overlay, or wedging. We calculated frequencies and percentages of suffocation deaths by mechanism and selected demographic and sleep-environment characteristics.

Fourteen percent of sudden unexpected infant death cases were classified as suffocation; these cases were most frequently attributed to soft bedding (69%), followed by overlay (19%) and wedging (12%). Median age at death in months varied by mechanism: 3 for soft bedding, 2 for overlay, and 6 for wedging. Soft-bedding deaths occurred most often in an adult bed (49%), in a prone position (82%), and with a blanket (or blankets) obstructing the airway (34%). Overlay deaths occurred most often in an adult bed (71%), and infants were overlaid by the mother (47%). Wedging deaths occurred most often when the infant became entrapped between a mattress and a wall (48%).

Safe sleep environments can reduce infant suffocation deaths. Increased knowledge about the characteristics of suffocation deaths can help inform prevention strategies by targeting highest-risk groups.