Swaddling is believed to create a calmer child who cries less and sleeps better. (Dmitry Naumov/iStock)

Swaddling a baby — the age-old technique of snugly wrapping an infant in a cloth or light blanket, with only the head exposed — is believed to create a calmer child who cries less and sleeps better.

However, might swaddling affect a baby’s risk for SIDS (sudden infant death syndrome)?

This study

Researchers analyzed data from four studies that involved 2,519 infants, including 760 whose deaths were attributed to SIDS. Overall, 323 infants had been swaddled, including 133 who died of SIDS.

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Swaddled babies placed on their side or stomach were twice as likely to have died from SIDS as were babies in those sleep positions who had not been swaddled. Risk was greater among babies 6 months or older, who the researchers noted had a “greater likelihood of rolling to a prone [stomach] position.” Risk of a SIDS death was somewhat less for all babies sleeping on their backs, but it was still greater among swaddled babies, compared with those who were not swaddled.

Who may be affected

Infants. New mothers often are shown how to swaddle their baby while still in the hospital. The technique keeps the infant warm and cozy, mimicking how the child felt in the womb. Precautions are needed, though, to prevent such problems as overheating and trouble breathing that may occur when a child rolls onto his or her stomach.

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The study authors wrote that “the current advice to avoid placing infants on their front or side to sleep may especially apply to infants who are swaddled.” In the United States, SIDS is the leading cause of death for infants 1 month to 1 year old, with most occurring when the child is 2 to 4 months old. Placing infants on their backs to sleep is considered a key element in preventing SIDS deaths. Medical experts do not know what causes SIDS. One prominent theory is that a combination of three factors — an undetected genetic abnormality, the development phase the infant is in and environmental stressors such as stomach sleeping, exposure to cigarette smoke and overheating — makes SIDS far more likely

Caveats

Infants in the study may have had other risk factors not included in the studies’ data. The analysis included some data from one study that had not been published.

Find this study

May 9 online issue of Pediatrics (pediatrics.aappublications.org; click on “Early Release”).

Learn more

Learn more about SIDS at kidshealth.org (enter parents’ site). Information on swaddling can be found at healthychildren.org.

The research described in Quick Study comes from credible, peer-reviewed journals.