Objectives: To determine sleep position variation during the first 6 months of life and to identify risk factors for prone sleeping.
Design: Cohort study of healthy term newborns recruited from November 1995 to September 1996 and followed up to age 6 months. Pediatricians were surveyed about sleep position advice. At recruitment, all parents were instructed to avoid prone sleeping. Parents were telephoned at 1 week and then monthly to ensure that they recorded sleep position. Investigators were unaware of sleep position until the infant was 6 months of age, when sleep log data and reasons for sleep position choice were ascertained.
Setting: Practice-based study conducted by the Children's National Medical Center Pediatric Research Network, Washington, DC.
Participants: A total of 402 consecutive healthy term newborns followed up by a Pediatric Research Network pediatrician were enrolled. Exclusion criteria were prematurity, a serious medical condition, and absence of a telephone. Of the 402 enrolled newborns, 348 (86.6%) completed the study.
Results: Only 34.0% of infants maintained a consistent sleep position. Prone sleeping increased from 12.2% at birth to 32.0% at 6 months. One third of pediatricians discussed sleep position beyond the newborn period. The following were associated (P<.05) with prone sleeping: male sex, lower maternal education level, single marital status, having siblings, and black race. Perceived infant comfort was the main reason for prone sleeping.
Conclusions: Most newborns are placed by parents in nonprone sleep positions. Pediatricians need to consistently reinforce the "Back to Sleep" message when the infants are 2 to 4 months of age because this is the most likely time that they are switched to prone sleeping and the highest risk period of sudden infant death syndrome. Parents should not use prone sleeping as a means of comforting infants.