Changes in sleep position during infancy: A prospective longitudinal assessment

Context.-Prone sleeping by infants has been associated with an increased risk of sudden infant death syndrome. Objective.-To document the prevalence of and identify risk factors for prone sleeping during the first 6 months of life. Design.-Prospective cohort study. Setting.-Eastern Massachusetts and northwest Ohio. Study Participants.-A total of 7796 mothers of infants weighing 2500 g or more at birth. Main Outcome Measures.-Maternal and infant characteristics related to prone sleeping at 1 month and 3 months of age. Results.-Between 1 month and 3 months of age, prone sleeping increased from 18% to 29%. At 1 month, prone sleeping was associated with the following maternal characteristics: non-Hispanic black or Hispanic race/ethnicity, younger age, less education, and higher parity. At 3 months, switching from nonprone to prone position was associated with mother's race/ethnicity of non-Hispanic black (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.2- 2.3) or Hispanic (OR, 1.5; 95% CI, 1.1 -2.2); younger maternal age (compared with mothers >34 years;. 1824 years, OR, 1.6; 95% CI, 1.2-2.2; <18 years, OR, 2.2; 95% CI, 1.2-4.3); increasing parity (compared with 1 child: 2 children, OR, 1.5; 95% CI, 1.2-1.8; ≥3 children, OR, 1.7; 95% CI, 1.4-2.2); and infant sex (male sex, OR, 1.4; 95% CI, 1.2-1.7). Conclusions.-If infant sleeping practices in the study communities are representative of practices throughout the United States, a substantial number of infants who slept nonprone at 1 month sleep prone at 3 months.