Objective: To critically analyze reports that show a relationship between sudden infant death syndrome (SIDS) and the prone sleeping position in infants.
Data sources: Peer-reviewed articles, published letters, book chapters, and local and national health statistics were used, without time or language restrictions. These studies represented three races, four continents, and seven countries; none was published in North America.
Study selection: No studies were ignored, but only those with case controls were reviewed in detail; we regarded a recent cohort analytic (prospective) study as particularly strong, in addition to six before-and-after (intervention) trials.
Data extraction: Hill's criteria for decision making were used to assess the quality and validity of the data.
Data synthesis: Without exception, all studies demonstrated an increased risk for SIDS associated with the prone sleeping position. The published likelihood ratios (relative risk or odds ratio) for SIDS in the prone position compared with SIDS in any other position ranged from 3.5 to 9.3 in seven studies. Publicity against the use of the prone position has been associated with reduction of SIDS by 20% to 67%, paralleling the reduction in use of the prone position, with no increase in deaths from aspiration or in other diagnostic categories.
Conclusions: We recommended avoidance of the prone sleeping position for infants in the first 6 months of life unless there is a specific medical indication for it. Reports from the Netherlands, Great Britain, Australia, and New Zealand indicate that avoiding the prone position for infants in the first 6 months of life could reduce the number of SIDS deaths by as much as 50%. Unfortunately, these findings have received little attention in North America. We offer here an analysis of these reports so that physicians can assess the evidence and advise parents accordingly.