Cosleeping and Biological Imperatives: Why Human Babies Do Not and Should Not Sleep Alone
By James J. McKenna Ph.D.
Edmund P. Joyce C.S.C. Chair in Anthropology
Director, Mother-Baby Behavioral Sleep Laboratory
University of Notre Dame
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In Japan where co-sleeping and breastfeeding (in the absence of maternal smoking) is the cultural norm, rates of the sudden infant death syndrome are the lowest in the world. For breastfeeding mothers, bedsharing makes breastfeeding much easier to manage and practically doubles the amount of breastfeeding sessions while permitting both mothers and infants to spend more time asleep. The increased exposure to mother’s antibodies which comes with more frequent nighttime breastfeeding can potentially, per any given infant, reduce infant illness. And because co-sleeping in the form of bedsharing makes breastfeeding easier for mothers, it encourages them to breastfeed for a greater number of months, according to Dr. Helen Ball’s studies at the University of Durham, therein potentially reducing the mothers chances of breast cancer. Indeed, the benefits of cosleeping helps explain why simply telling parents never to sleep with baby is like suggesting that nobody should eat fats and sugars since excessive fats and sugars lead to obesity and/or death from heart disease, diabetes or cancer. Obviously, there’s a whole lot more to the story.
As regards bedsharing, an expanded version of its function and effects on the infant’s biology helps us to understand not only why the bedsharing debate refuses to go away, but why the overwhelming majority of parents in the United States (over 50% according to the most recent national survey) now sleep in bed for part or all of the night with their babies.
That the highest rates of bedsharing worldwide occur alongside the lowest rates of infant mortality, including Sudden Infant Death Syndrome (SIDS) rates, is a point worth returning to. It is an important beginning point for understanding the complexities involved in explaining why outcomes related to bedsharing (recall, one of many types of cosleeping) vary between being protective for some populations and dangerous for others. It suggests that whether or not babies should bedshare and what the outcome will be may depend on who is involved, under what condition it occurs, how it is practiced, and the quality of the relationship brought to the bed to share. This is not the answer some medical authorities are looking for, but it certainly resonates with parents, and it is substantiated by scores of studies..."
