Swaddling a baby can help your little one sleep better and cry less. But a new review of studies published in the journal Pediatrics has found the practice may be linked to a scary consequence: sudden infant death syndrome, or SIDS, which kills about 2,500 infants every year in the United States.
Researchers at the University of Bristol in the U.K. reviewed four studies, which took place over four decades in England, Australia, and the United States. Overall, the review included 760 cases of SIDS and 1,759 control subjects, the New York Times reports. The studies examined possible associations between SIDS and swaddling an infant.
Though all four studies were slightly different, the Bristol researchers were able to determine that there was an increased risk of SIDS if a baby was swaddled. The risk was highest if the swaddled baby was placed on his or her stomach, the risk was slightly less if the baby was placed on his or her side, and the risk was lowest if the swaddled baby was placed on his or her back. The majority of infants who died from SIDS seemed to have moved onto their stomachs during sleep.
The risk of SIDS was also higher when the infant was older and swaddled. According to the researchers, as babies get older, they are more likely to be able to move into unsafe positions while swaddled. Most babies can roll over starting at 4 to 6 months old, so the researchers suggest parents stop swaddling them for sleep by then.
"On a practical level what parents should take away from this is that if they choose to swaddle their babies for sleep, always place them on their back and think about when to stop swaddling for sleep as their babies get older and more able to move," researcher Anna Pease, PhD, said in a statement.