Risk Factors, Protective Factors, and Current Recommendations to Reduce Sudden Infant Death Syndrome: A Review.

Importance: Sudden infant death syndrome remains the leading cause of death in infants aged 1 month to 1 year in the United States. Observations: While its exact cause is unknown, sudden infant death syndrome is believed to be multifactorial, ie, occurs in infants with underlying biological vulnerability who experience an exogenous stressor, such as prone/side sleeping or soft bedding, during a critical developmental period. Much genetic and physiologic evidence points to impaired arousal responses to hypercarbia and hypoxia, which ultimately leads to asphyxia. Known risk factors for infants include prone and side sleeping, soft bedding, bed sharing, inappropriate sleep surfaces (including sofas), exposure to tobacco smoke, and prematurity; protective factors include breastfeeding, pacifier use, room sharing, and immunizations. Conclusions and Relevance: Despite our improved understanding of the physiologic mechanisms that cause sudden infant death, the mainstay of risk reduction continues to be a safe sleep environment, as most infants who die suddenly and unexpectedly do so in unsafe sleep environments.