Maternal and infant characteristics associated with prone and lateral infant sleep positioning in Washington State, 1996-2002

Background: In 2005, the American Academy of Pediatrics recommended that parents avoid placing their infants in either the lateral or prone sleep positions due to an increased risk of Sudden Infant Death Syndrome (SIDS). We aimed to identify factors predictive of both infant lateral and prone sleep positioning.

Methods: We identified mother-infant pairs who took part in the Pregnancy Risk Assessment Monitoring System survey in 1996-2002 in Washington State. These participants were linked to infant birth certificate and mother-infant birth hospital discharge data. We employed backward stepwise predictive modeling to identify statistically significant (p<0.05) predictors of sleep positioning. Separate models for lateral and prone positioning were developed. Survey methods were used to account for the complex survey sample design.

Results: We identified 11,340 mother-infant pairs. Overall 65.4% of mothers placed their infants to sleep in the supine position, 10.6% prone and 24.1% lateral. Infant characteristics predictive of prone sleep positioning included earlier year of birth and male sex; mother's characteristics were residence outside Seattle-King county, primiparity, United States born (vs. foreign born) and African-American, Native American or Hispanic (vs. White) race. Predictors of lateral sleep positioning included an earlier year of infant's birth, prematurity and low birth weight; and mother's primiparity, residence in a rural county, being a race/ethnicity other than Caucasian, and receiving Medicaid and other government benefits during pregnancy.

Conclusion: Our findings suggest that risk factors for prone and lateral sleep positioning differ, and both sets of factors should be considered when devising SIDS prevention strategies.