What are Swaddles and Sleep Sacks?

This content was created by the National Sleep Foundation


Learn the real deal on how you should dress your baby for sleep.


Swaddles, sleep sacks—whether you’re looking for a gift on a friend’s baby registry or preparing to bring your own little one home, options for baby sleepwear can all start to sound like a foreign language. The one common theme with both options: safe sleep. Since infants aren’t able to move purposefully yet, covering them with loose blankets for warmth while they sleep can actually lead to suffocation and increase the risk for SIDS (sudden infant death syndrome). Both swaddles and sleep sacks—which are made by a variety of different companies—can provide a safer sleep environment for babies.

Sleep Sacks

To make sure that your baby stays at the right temperature during the night, a sleep sack is one type of sleepwear that you could try putting on your little one. It's essentially a wearable sleeping bag or a nightgown that’s closed at the bottom. Some styles are sleeveless for warmer weather, and others are long-sleeved and made of cozy fleece for cooler temps. But all encapsulate the baby’s legs in a loose layer of fabric that takes the place of a blanket with less risk.


At its most basic, a swaddle is simply a large blanket that you can wrap tightly around a baby, tucking in the loose ends to create a sort of baby burrito. The idea: Babies, who are used to being in the very small space of their mother’s womb, feel more secure when they’re wrapped up tightly. And since the blanket is wrapped and tucked securely around the baby, it’s considered safer than using a loose blanket. Nurses often teach new parents how to swaddle their baby in the hospital.

Sleep Sack-Swaddle Hybrids

Not all parents love playing blanket origami, however—especially in the middle of the night. So many companies have now created infant sleepwear with Velcro tabs that you can simply pull across your baby’s arms to create the burrito (or straightjacket) effect. These essentially look like sleep sacks with the added feature of easy swaddling for babies who like to be wrapped tightly.

The Bottom Line

When it comes to whether or not to swaddle your baby for sleep, your baby may very well have his own preference. Some infants love it, and sleep soundly, while others manage to kick and thrash free from any swaddle that their parents try. If you’re concerned about your little one’s sleep habits, talk to your pediatrician.