Does swaddling increase the risk of SIDS in infants?

What does swaddling mean?

Swaddling is the snug wrapping of a blanket around an infant to reduce or minimize the movements of the arms and legs. Swaddling is a common infant calming tool and is used frequently during the newborn period (first 21 days of life) to create a sensation similar to the constricted and tight environment of the womb before birth.

This is what a swaddled baby looks like:

Swaddling has been used for centuries to help calm babies and control their body temperatures after birth. Most likely you have already seen your baby swaddled if you gave birth in a hospital and the nurses snuck off with your baby at some point (generally for the first bath). When your baby was returned to you, he or she was most likely tightly wrapped in a hospital blanket and looked like a baby burrito.

The prevalence of swaddling across cultures gives validity to its usefulness. However, some researchers wanted to investigate if swaddling also had risks.

Why “swaddling” may increase the risk of SIDS during infancy

The new research looked at data of sleeping infants in three geographic regions (England, Australia, and the United States) over the period of 20 years. From the data analyzed, the researchers found that swaddling does increase the risk of SIDS, especially as the age of the infant increased. For example, swaddled infants 6 months of age or older had the greatest risk of SIDS.

This finding, that older swaddled infants were at greater risk, is logical because older infants have greater strength over their bodies to move, but still lack well-developed coordination. For example, newborn infants cannot hold up their heads due to lack of neck strength. Yet, by 3-4 months, infants can hold their heads up even when being moved from a reclined to sitting position. Similarly, newborn infants cannot roll over because they lack arm strength. Yet, most infants learn how to roll over by 3 months or so, although some little ones kick their legs so hard that they flip over earlier.

What does all this mean? Well, if an infant rolls over onto his or her tummy, but lacks strength or coordination to lift his or her head or roll in the opposite direction, he or she will be stuck breathing into the mattress. Then, if on top of breathing into the mattress, they are swaddled and the swaddling loosens so that part of the it covers their head or face, then the infant will have less air available to breathe and thus will be rebreathing their own exhaled air.

Therefore, it makes sense that older infants who can roll and move around more would be more likely to become facing down and have blankets covering their heads which would increase the risk of SIDs.

Additionally, the researchers found that the sleep position of the swaddled infants influenced their SIDS risk. Infants who were placed on their back while sleeping had the lowest risk while infants who were placed on their tummies to sleep had the greatest risk. All major pediatric organizations recommend that all babies, swaddled or unswaddled, sleep on their backs. Belly sleeping is not recommended for any babies.

And finally, the researchers noted that there were no precise definitions of swaddling in the studies that were analyzed. What this means is that what was defined as swaddling was not clearly explained. The infant picture above shows a baby swaddled with a thin linen blanket. However, a quick search on the Internet will reveal a mind-boggling amount of blankets and apparatuses for infant swaddling. The researchers are unclear what swaddles were employed and how the differences in swaddles may have affected the results.

5 tips to reduce the risk of SIDS during infancy

Therefore, the take away information from this new research for parents to reduce the risk of SIDS includes:

1. Keep baby on their back for sleep. All infants should be placed on their backs to sleep. No major pediatric group recommends belly sleeping.
2. Swadding has been shown to increase the risk of SIDS as infants grow; infants 6 months or more have the greatest risk. Limit swaddle use to the first months of life. Be sure to use a lightweight blanket.
3. Babies should sleep on firm surfaces. Avoid sofas, thick blankets, fluffy mats, or waterbeds.
4. Keep crib as bare as possible. Remove all loose blankets, pillows, stuffed animals, and pets from sleeping area.
5. Avoid smoking around infants. Second-hand smoke increases SIDS risks.

The benefits of swaddling for infant calming and body temperature control must be weighed against the risk of SIDs with swaddling use.

*Pease AS, Fleming PJ, Huck FR, et al. Swaddling and the risk of sudden infant death syndrome: a meta-analysis. Pediatrics. 2016; doi: 10.1542/peds.2015.3275