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: 18-24 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; > or =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.