Seasonality in sudden infant death syndrome--United States, 1980-1987.

Sudden infant death syndrome (SIDS) is the sudden death of an infant less than 1 year of age that remains unexplained after a complete postmortem investigation, including autopsy, examination of the death scene, and review of the case history. SIDS, which usually occurs during sleep, is the leading cause of death in the postneonatal period (i.e., from 28 days through 364 days) and the eighth leading cause of years of potential life lost in the United States (1). The risk for SIDS is greatest for infants aged 1-4 months and during the cold season of the year (2); however, an independent contribution of the season of birth to the etiology of SIDS has not been consistently demonstrated (3). This report summarizes an assessment of the association between the risk for SIDS and an infant's month of birth, month of death, and age at death.