Safe Sleeping: Reducing the Risk of SIDS

Carol Berkowitz, MD

In 1992, in an effort to prevent Sudden Infant Death Syndrome (SIDS), the Back to Sleep Campaign was waged. The campaign advised caregivers to place young infants on their backs, supine, for sleep. The recommendation seemed counter-intuitive to many who feared that back-sleeping infants may vomit and inhale the vomitus into their lungs. The scientific evidence for the recommendation was strong, based on data that in nations where infants were placed on their backs, SIDS occurred at a significantly lower rate. As a result of the campaign, the incidence of SIDS in our nation has been reduced by 50% to 8 per 10,000 live births.

With the reduction in the incidence of SIDS and the development of more careful investigations of the circumstances around the sudden death of infants, it became apparent that some infants who died of SIDS were co-sleeping, sleeping not alone in an infant crib, but in a bed or on a sofa with an adult. In many jurisdictions, the coroner would no longer consider the death SIDS, but would attribute the death to co-sleeping.

What is the evidence that young infants who sleep in the same bed as their caregivers are at greater risk of suddenly dying? There are a number of large epidemiological studies that show that the risk of suddenly dying increases 20 to 40 fold in young infants who co-sleep. The risk is highest in the first eight to twelve weeks of life, and is greatest in infants of mothers who smoke, take drugs, or consume alcohol.

What are the factors that may contribute to an infant's sudden death when co-sleeping? The most obvious concern relates to overlaying, when the caregiver lies on top of an infant. Overlaying as a cause of infant death was mentioned in the Bible:

And this woman's child died in the night;
because she overlaid it.
Kings I 3:19

Overlaying may result in occlusion of the infant's nose, compression of his chest (not allowing it to expand during breathing), or compression of an infant's neck, cutting off circulation to an infant's brain. There are additional factors which may contribute to an infant's death during co-sleeping. Studies show that on average a mother and infant sleep with their faces about eight inches apart. A mother's exhaled breath, high in carbon dioxide, is blown into an infant's face, increasing the carbon dioxide content in the infant's environment. Increased levels of carbon dioxide may act to suffocate the infant.

Increased warmth in an infant's environment may also be a factor in sudden infant death. It appears that over-bundled infants have a higher rate of SIDS, and co-sleeping infants may be more prone to overheating because of adjacent bodies as well as adult bedding.

The presence of bedding, particularly pillows and comforters, may also serve to impede an infant's respiratory efforts. Adult beds are softer than infant cribs, and infant airways are more likely to become blocked by bedding materials. In addition, infants may become wedged between the head board and the mattress. Wedging, when the infant's head and body gets trapped between objects, is a particular problem when co-sleeping occurs on sofas. Infants should not be placed on a sofa to sleep because they can easily wiggle around, become entrapped, but then not be able to extricate themselves from between the cushions.

The safest way for infants to sleep is on their backs (supine), in a crib that meets the standards established by the Consumer Product Safety Commission (CPSC), and without pillows, comforters or stuffed animals in the crib. For parents who so wish, cribs may be placed in the same room as the parent's bed. Infant sleeping in proximity to the parents is particularly encouraging for breastfeeding mothers, especially immediately after the birth of the infant.

There are a number of infant products that may facilitate sleeping in proximity. Infant bassinets have been used for many years to allow infants to sleep close to their parent's bed. Bassinets are not reviewed by the CPSC, so parents should carefully examine them to be certain they have a firm mattress, no pillow or other hazards that may suffocate their infant. For families unable to afford a bassinet, a laundry basket may be used as an initial sleep environment. Other products, such as Arm's Reach Co-Sleeper, have also been developed to keep an infant in proximity without actually placing the infant in the parent's bed.

Once infants are older, the risk of sudden death related to co-sleeping appears to be much reduced. In many cultures, infants and young children traditionally sleep with their parents. There is no evidence that such practices either help or harm children, and many individual factors, such as cultural beliefs, parental relationships, and family sleep practices need to be considered. It is important to recognize, however, that in many of the cultures where co-sleeping is prevalent, families do not sleep in typical Western beds, but rather sleep on the floor on yos (Korean floor mat) or on futons.

Parents can obtain additional information about safe sleeping by visiting the website of the Consumer Product Safety Commission at or the American Academy of Pediatrics at

Carol Berkowitz, M.D. is a Professor of Clinical Pediatrics at the David Geffen School of Medicine at UCLA, and Executive Vice Chair of the Department of Pediatrics at Harbor-UCLA Medical Center in Torrance, California. She is the President of the American Academy of Pediatrics.
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