Mothers who slept in the same bed with their infants breastfed more and longer than those who slept separately, researchers found, but the practice of bed-sharing has provoked an ongoing controversy over whether it leads to Sudden Infant Death Syndrome (SIDS).
In a univariate analysis, a higher cumulative bed-sharing score -- quantifying how often mothers slept with their infants -- was associated with a longer duration of any breastfeeding (HR 0.88, 95% CI 0.84-0.91, P<0.001) and exclusive breastfeeding (HR 0.94, 95% CI 0.90-0.99, P=0.01), according to Fern R. Hauck, MD, of the University of Virginia in Charlottesville, and colleagues.
In addition, in a multivariate analysis, a high bed-sharing score was associated with a lower likelihood of not breastfeeding at all during the first year of life (HR 0.85, 95% CI 0.79-0.90, P<0.001), the researchers reported online in JAMA Pediatrics.
Despite the well-recognized benefits of breastfeeding for infants, rates of exclusive breastfeeding in the U.S. remain below the recommended rates of 46.2% and 25.5% at 3 and 6 months, with CDC reporting current rates at 33% and 13.3%, respectively.
The American Academy of Pediatrics recommends a "separate but proximate sleeping environment" for young infants, noting the risk of SIDS, but some experts and groups have suggested that bed-sharing can help encourage breastfeeding.
"This is a very difficult question, because the data are very good that breastfeeding protects against SIDS," Ruth A. Lawrence, MD, of the University of Rochester, told MedPage Today.
"This has been studied over and over around the world and therefore if bed-sharing facilitates breastfeeding, which we know it does from this study and many others, it would be better to facilitate breastfeeding than to keep a mother from bed-sharing," said Lawrence, who was not involved in the study.
Hauck and colleagues previously reported in the Infant Feeding Practices Study II that more than 40% of mothers were bed-sharing when their infants were 2 weeks old, and that the majority of mothers who did so cited ease of breastfeeding as a reason.
To further explore the effects of bed-sharing on breastfeeding, the researchers analyzed additional data from 1,846 participants in that longitudinal cohort who had responded to multiple questionnaires about these practices during their infants' first year.
Bed-sharing scores ranged from zero to seven, with a score of zero being no bed-sharing and scores above five representing frequent bed-sharing.
Participants' mean age was 29 years, 85% were white, and 83% were married. Most had at least some college education.
The mean infant age when bed-sharing first began was at 8.3 weeks, and the mean cumulative bed-sharing score was 2.3.
Among mothers who reported breastfeeding at 2 weeks, the mean duration was 30.7 weeks. The mean duration of exclusive breastfeeding was 9.7 weeks.
Longer duration of both any and exclusive breastfeeding was most notable for infants who began bed-sharing earlier.
In the multivariate analysis, each 1-point higher bed-sharing score lowered the likelihood of stopping breastfeeding by 15.5%, Hauck and colleagues noted.
However, the high bed-sharing score was not significantly associated with a lower risk of stopping exclusive breastfeeding during the first 6 months (HR 0.96, 95% CI 0.89-1.04, P=0.31), they reported.
While in the multivariate analysis the association for bed-sharing and duration of breastfeeding wasn't significant, the researchers noted that these factors were associated with shorter duration of exclusive breastfeeding:
- Some college education, HR 1.36 (95% CI 1.20-1.55, P<0.001)
- High school education or less, HR 1.67 (95% CI 1.41-1.99, P<0.001)
- Nonwhite race, HR 1.47 (95% CI 1.25-1.72, P<0.001)
- Mother's returning to work within a year, HR 1.36 (95% CI 1.21-1.53, P<0.001)
- No previous breastfeeding, HR 1.24 (95% CI 1.09-1.41, P=0.001)
- Not having planned to breastfeed exclusively, HR 2.32 (95% CI 2.03-2.64, P<0.001)
- Smoking after the birth, HR 1.65 (95% CI 1.36-1.99, P<0.001)
"This study provides strong evidence that bed-sharing promotes breastfeeding by increasing breastfeeding duration, with the greatest effect found among frequent bed-sharers," the researchers observed.
"Parents need to know that bed-sharing may make breastfeeding easier to maintain and therefore it is tempting for them to do it. On the other hand, they deserve to know that it comes with a risk to their infant's safety. Health professionals need to address these two sides when educating parents, so that informed decisions can be made," Hauck and colleagues stated.
Lawrence disagreed with the researchers' perspective, however.
"Unfortunately, they concluded that bed-sharing increases the risk of SIDS. Well it does, in bottle-fed babies, but it does not in breastfed babies," she said in an interview.
A limitation of the study was the predominance of women who were white and of high socioeconomic status.
The data collection was supported by the Department of Health and Human Services.
The authors reported no financial disclosures.
- Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner