Sudden infant death syndrome is significantly more likely in infants who are swaddled and placed on the front or side, according to a meta-analysis by Anna S. Pease of the University of Bristol (England), and her associates.

They looked at four studies covering 760 cases of SIDS and 1,759 controls. The odds ratio for swaddling when infant death occurred was 1.58. Risk was highest when swaddled infants were placed on their stomachs, with an OR of 12.99, though risk was also high for children placed on their sides, with an OR of 3.16. Swaddled infants placed on their backs had the lowest risk, with an OR of 1.93.

Some evidence suggested that swaddling risk increased as the infant got older, with an odds ratio of 2.53 in children older than 6 months; however, cases were uncommon and the relationship is not definitive.

“Given the marked increase in infants swaddled and found prone (rather than placed prone), coupled with an increased risk of swaddling with increased age regardless of sleeping position, health professionals and current guidelines should consider an appropriate age limit at which swaddling should be discouraged,” the investigators concluded.

Find the full study in Pediatrics (2016. doi: 10.1542/peds.2015-3275 ).