Trends in infant bed sharing in the United States, 1993-2000: the National Infant Sleep Position study

BACKGROUND: Bed sharing with parents has been described as both beneficial to infant well-being and as a potentially lethal situation. OBJECTIVE: To examine trends in bed sharing between infants and caregivers, and the factors that influence this behavior. DESIGN: Annual nationally representative telephone surveys conducted between 1993 and 2000. SETTING: The 48 contiguous United States. PARTICIPANTS: Nighttime caregivers of infants born within 7 months prior to interview between 1993 and 2000. Approximately 1000 interviews were conducted each year for a total sample of 8453 nighttime caregivers. MAIN OUTCOME MEASURES: Where and with whom the infant usually slept at night in the preceding 2 weeks. RESULTS: Forty-five percent of infants spent at least some time at night on an adult bed in the last 2 weeks. Between 1993 and 2000, the proportion of infants usually sharing an adult bed at night increased from 5.5% to 12.8%. More than 90% of infants who "usually" slept on an adult bed shared it with their parents. In a multivariate analysis, factors associated with increased probability of routine bed sharing included: maternal age less than 18 years (odds ratio OR] = 2.26; 95% confidence interval CI], 1.22-4.21), maternal race or ethnicity reported as black (OR = 4.04; 95% CI, 3.04-5.36) or as Asian or "other" (OR = 2.72; 95% CI, 1.74-4.22), household income less than $20,000 (OR = 1.49; 95% CI, 1.15 = 1.92), living in the Southern states compared with living in the Midwest (OR, 1.59; 95% CI = 1.23, 2.06), and infant age less than 8 weeks (OR = 1.60; 95% CI, 1.10-2.33). Living in the Mid-Atlantic compared with the Midwest (OR = 0.63; 95% CI, 0.44-0.90), and being born with low birthweight and preterm (OR = 0.32; 95% CI, 0.14-0.74) were associated with decreased probability of routine bed sharing. CONCLUSIONS: Bed sharing as a routine practice is growing in the United States. Given that this practice seems to be widespread and strongly influenced by cultural factors, more studies of the consequences of bed sharing are needed to inform health care providers and parents on the risks and benefits.