Although bed-sharing, a type of cosleeping in which parents and children sleep in the same bed,1-3 is a customary sleeping arrangement for children in many countries and cultures,2 it remains relatively uncommon in the United States.4,5 Ambivalence toward bed-sharing in the United States may be due in part to different messages about its risks and benefits. A study of 40 US parenting books on sleep, for example, found that while bed-sharing was endorsed in 28% of the books, it was opposed by 40%.5 The remaining 32% of books abstained from taking a position on bed-sharing. Proponents of bed-sharing argue that it facilitates breastfeeding,6,7 encourages bonding between a mother and her child,8 and regulates infant breathing.9 Yet the American Academy of Pediatrics recommends against bed-sharing during infancy, citing epidemiologic evidence that bed-sharing increases the risk of sudden infant death syndrome under certain conditions (ie, if the mother smokes or is overtired; if the child is younger than 11 weeks).10 Furthermore, bed-sharing has been found to exacerbate sleep problems in children in addition to distress among parents.1,11,12 Notably, advice (in favor or against bed-sharing) depends on the age of the child. This study examines bed-sharing at 1 to 3 years of age, when a child is no longer at risk for sudden infant death syndrome.

Little is known about the potential developmental consequences of bed-sharing for toddlers and older children in the United States, where bed-sharing is not the norm.4 Most studies with US samples have examined sleep problems rather than indicators of cognitive and behavioral development as outcomes. To our knowledge, only 2 longitudinal studies with US families13,14 have examined the influence of bed-sharing on later cognition or behavior. The first study (N = 330) found no association between bed-sharing at age 2 years and emotional or behavioral problems 1 year later in a community sample.13 However, a significant proportion of the families with low socioeconomic status (SES) in that study were lost at follow-up. The second study (N = 205) also found no association between bed-sharing infancy and early childhood (3, 4, and 5 years) and child behavior at age 6 years.14 Interestingly, higher cognitive competence scores were found among bed-sharers. However, that sample consisted of relatively well-educated non-Hispanic white families, of which only 6% reported regularly sharing a bed. Given its homogenous sample with a small percentage of bed-sharers, this study has limited generalizability, as black and Hispanic American families are more likely than non-Hispanic white families to practice bed-sharing.12,15 Because bed-sharing is also more common among lower-SES families in the United States,13,16 there is a need to examine whether bed-sharing poses an additional risk for the cognitive and behavioral outcomes of children already at risk.17,18

This study examined the predictors and consequences of mother-child bed-sharing at 1, 2, and 3 years of age in a racially/ethnically and geographically diverse sample of low-income families across the United States. We began by categorizing families according to how often they reported bed-sharing at these 3 time points (never, 1 time point only, and 2-3 time points), and then predicted membership in these categories based on family sociodemographic characteristics, observed maternal parenting behaviors, and maternal depressive symptoms. These predictors were selected based on past studies identifying child age, parental education, SES, the number of children in the home, maternal depressive symptoms, and single parent status as correlates of bed-sharing.1,19-22 We also included maternal parenting behaviors (supportiveness, negative regard, and detachment) that may be associated with bed-sharing. Associations between bed-sharing across ages 1 through 3 years and a range of cognitive and behavioral outcomes at age 5 years were then examined. When bivariate associations were found, multivariate models of those outcomes were used to test whether bed-sharing remains predictive when demographic characteristics, maternal depressive symptoms, and maternal parenting behaviors are controlled.

On the basis of previous studies,12,13 we expect that bed-sharing will be less prevalent among non-Hispanic whites compared with blacks and Hispanics. We also expect that maternal education will be negatively associated with bed-sharing, and that maternal depressive symptoms will be positively associated with bed-sharing.21,22

We expect bed-sharing to be bivariately inversely associated with cognitive and behavioral outcomes owing to the higher prevalence of bed-sharing among lower SES and racial and ethnic minority families. Furthermore, we expect to find associations between bed-sharing and poorer cognitive and behavioral outcomes, even in a multivariate context. Although past research has failed to find such associations,13,14 bed-sharing is associated with sleep problems, which are themselves associated with behavior and cognitive problems.23-25 Past studies may have lacked the statistical power necessary to detect associations between bed-sharing and behavior. The large number of bed-sharers in our sample should offer greater statistical power than was available in past studies.