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Baby and toddler

Sleep sack

A wearable blanket a baby sleeps in, zipped over their clothes, that keeps them warm without a loose blanket in the crib.

What It Means

A sleep sack, also called a wearable blanket, is a sleeveless bag-shaped garment a baby wears over their pajamas to sleep. It takes the place of a loose blanket, which the American Academy of Pediatrics (AAP) says doesn't belong in the crib. Some sleep sacks leave the arms free and some add a swaddle wrap, and the AAP's guidance treats those two kinds differently once a baby starts trying to roll.

Try It: Compare Four Ways to Keep a Sleeping Baby Warm

Pick an option to see what the AAP's guidance says about it once a baby is in the crib.

Before any sign of rolling

Fine

Once the baby tries to roll

Fine, as long as you like

How Parents Say It

  • "Zip her into the sleep sack and she's out."
  • "We switched to an arms-out sack when he started rolling."
  • "No blanket, he's got his sleep sack on."

The Breakdown

Sleep sacks by stage, per the AAP

StageWhat to useSource
NewbornNewbornA baby in the first 28 days of life, the stage doctors also call the neonatal period. See more weeksA swaddle or a sleep sack, always on the backHealthyChildren.org; Safe to Sleep
First signs of trying to rollStop any sack or wrap that holds the arms, chest and body inHealthyChildren.org
After thatA sleep sack that leaves the baby free to move, for as long as you likeHealthyChildren.org
Any ageNothing weighted, and no loose blanket in the cribAAP 2022

Picking one. Check the label for the size and weight range and choose the one that fits your baby now. Some sacks close with a swaddle wrap and some leave the arms out, so check which kind you're buying if your baby is near the rolling stage.

When to talk to your pediatrician. Ask if you're unsure how warmly to dress your baby for sleep, or whether a particular product fits the AAP's guidance.

Good to Know

Weighted sleep sacks are out. The AAP's 2022 policy says weighted sleepers, weighted swaddles and weighted blankets shouldn't be placed on or near a sleeping baby. In April 2024 CPSC Commissioner Richard Trumka warned that weighted infant products are unsafe for sleep, and Target, Walmart, Nordstrom and Babylist committed to stop selling them. A sleep sack still goes on a baby who sleeps on their back, alone, on a firm, flat surface. If your baby isn't breathing or can't be woken, call 911.

FAQ

Is a sleep sack safe for a newborn?

The AAP prefers sleep clothing such as a wearable blanket or sleep sack to a loose blanket for keeping a baby warm. Put the baby down on their back, and skip any sack that's weighted.

How long can a baby use a sleep sack?

HealthyChildren.org says a sleep sack that doesn't swaddle and lets the baby move freely can be used as long as you want. A sack that compresses the arms, chest and body should stop once the baby shows signs of starting to roll.

What's the difference between a sleep sack and a swaddle?

A swaddle wraps the baby's arms and body snugly, and it has to stop at the first signs of rolling. An arms-free sleep sack keeps the baby warm while leaving them free to move, so it can carry on after that point.

Do It in Buhata

Shopping and Handoff Card

Add the next size of arms-free sleep sack to your Shopping list in a Household Space in Buhata so it's ready before the current one gets snug.

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Related Terms and Categories

  • Safe sleep

    The AAP's rules for lowering the risk of SIDS and suffocation: baby on the back, alone, on a firm flat surface in their own sleep space, every sleep.

  • Crib transition

    Moving a child from a crib to a toddler bed or regular bed, which the AAP ties to height or to the crib rail getting too low for them.

  • Newborn

    A baby in the first 28 days of life, the stage doctors also call the neonatal period.

Baby and toddler

Sources

HealthyChildren.org (AAP), "Swaddling: Is it Safe for Your Baby?"; American Academy of Pediatrics, "Sleep-Related Infant Deaths: Updated 2022 Recommendations for Reducing Infant Deaths in the Sleep Environment," Pediatrics, 2022; CPSC, Commissioner Richard Trumka, "Beware: Weighted Infant Swaddles and Blankets Are Unsafe for Sleep; Retailers Should Consider Stopping Sales" (2024); CPSC, Commissioner Richard Trumka, "Target, Walmart, Nordstrom, and Babylist Commit to Stop Selling Weighted Infant Products" (2024); NICHD Safe to Sleep, "Safe Sleep Environment for Baby"

Last updated .