When you’ve been a sleep coach as long as I have, it really seems that you’ve heard every question that could possibly come up surrounding how to get a baby to sleep through the night and take great naps. One question that I get surprisingly often is, “Are baby sleep sacks safe?” Or the related question, “Is using a sleep sack required for sleep training to be successful?”
Are Baby Sleep Sacks Safe?
The answer is, it depends. I should share with you that I am a stickler about crib and sleep safety, probably more so than any other sleep coach or parent I’ve ever met. While I stand by everything I say, it’s important to understand that my number one motivation at all times is to make sure babies are always 100% safe during sleep. That can sometimes mean that I advise parents to do, or not do, things that might make it a bit harder on them, but ultimately baby is better off because they are safe.
An example would be my hardline approach on the following: if parents are asleep, babies of all ages should only sleep in completely empty cribs or Pack n Plays. Which leads me to share my thoughts on whether or not sleep sacks are safe. After 8 weeks of age, the only type of sleep sack a baby should be sleeping in is one that is sleeveless.
The American Academy of Pediatrics now advises families to stop swaddling their children as soon as baby shows signs of being able to roll over, or 8 weeks of age, whichever comes first. If you choose to transition your child from a swaddle to a sleep sack, you should only transition them to a sleeveless sleep sack.
Why Keep Arms Free?
Sleep sacks which cover the arms tend to have a lot of excess fabric, and this fabric can encumber a child’s ability to move freely. Most babies tend to practice rolling in their crib. Which means you, the parent, could be asleep/not monitoring baby. If they become trapped on their stomach because the excess fabric on their arms prevents them maneuvering their body freely, the situation could produce dire consequences.
As your child grows into an older infant and toddler, you may feel that they have gained the dexterity to move themselves around freely. Check with your pediatrician to confirm that your child sleeping in a sleep sack that is not sleeveless is safe.
Are Baby Sleep Sacks Necessary?
Are sleep sacks even necessary? I tell families that the choice to place your child in a sleep sack is 100% personal preference. I don’t think it’s necessary for a child to sleep in a sleep sack in order to sleep well. Nor do I believe using one impacts a child’s ability to sleep well.
After ensuring baby can move freely in whatever sleep sack they’re wearing, families should next ensure that baby cannot overheat due to wearing a sleep sack. Indeed, babies are at much higher risk of overheating than being too cold. So as long as families feel their baby can maintain a safe temperature, using a sleep sack is just fine.
I often think sleep sacks are just as much for peace of mind for parents (to ensure that baby is warm and cozy) as they are for the comfort of the child. So if you deem one is necessary and it is used safely, go for it!
To recap, are baby sleep sacks safe?:
- Your number one concern when it comes to your child’s sleep should be safety.
- As long as your child’s sleep sack is sleeveless, rest assured they are safe.
- Remember that sleep sacks that cover your baby’s arms can make it dangerously difficult for them to extricate themselves from whatever position they get themselves into in their crib.
- Avoid using sleep sacks with sleeves until your pediatrician confirms they have reached a sufficient level of dexterity.
- At the end of the day, sleep sacks make parents feel as comfortable as they make baby feel.
- As long as baby can’t overheat and is safe, a sleep sack is a great choice!
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I have a question regarding sleeveless vs. Long sleeve sleepsacks. You mention that sleep sacks with sleeves are not safe. How is a long sleeve sleep sack different from placing a child in a long sleeve onesie with a sleeveless sleepsack on top? Thank you!
It really comes down to a child’s ability to move freely. Since new sleep sacks come on the market anytime, if the sleeves are fitted to the body (say, as they would be with a onesie), that would be fine at any age. It is it sleep sacks that cover the arms with bulky fabric that I would avoid for younger infants. I personally find completely sleeveless sleep sacks to be the safest choice.
Hi Natalie, our baby is 9 weeks old now and we’re trying to find the best remedy besides a swaddle sack with velcro. We have a sleeveless sack but she flails her hands so much during sleep that she wakes herself up sometimes. What would Your suggestion be, to stick it out and push the sleeveless sack or continue velcro swaddling because she keeps her hand close to her face and sometimes takes them out as well? ♀️ I’m so confused.
If the pediatrician says it’s safe for baby to continue sleeping in a swaddle, you could keep trying it. If they say it’s not safe for her to stay in a swaddle, switch to the sleep sack and tough it out <3
Hello, my baby is 3 months and 3 weeks and still seems to have his startle reflex. He breaks out of any swaddle I’ve tried these days and the trouble with a sleep sack is that he kicks his legs against it like crazy. He’s a very kicky baby and it’s like he can’t help but kick against it and he doesn’t sleep. I usually just put him to sleep in a onesie with footies but I’m trying to get him to go to sleep on his own in preparation for the sleep regression, without holding him to sleep and then setting him in his crib. I’m noticing as he falls asleep on his own the startle reflex prevents him from sleeping long or well. I’m lost on what to do.
Going to sleep on his own is sleep training 😉 I’d start that any time you’re ready after 16 weeks. This will resolve the startle reflex, etc.
Seems like the sleeveless sleep sacks have a lot of extra material that could bunch up around a babies face making it hard to breathe. Thoughts?
Hi Laura!! Great question. I suppose each parent must decide for themselves if a sleep sack is safe for their baby. If there is ANY risk of material blocking a baby’s face, that particular sleep sack should NOT be used!
Dear Natalie, What other alternative is there if I decide to not use a sleep sack? Thank you.
A footed sleeper or any other type of pajamas.
My 8 1/2 month old has freezing hands in the middle of the night with the cooling temperatures. I have been looking at zipadee zip sleep sacks. Even though they cover his arms, they claim to be a safe solution and allow baby to move freely. Would you mind giving your opinion on their safety? At his age, is it still a concern in your opinion? Also, do you have any other suggestions to keep his hands warm at night? Thanks for your help and time!
I’d check with your pediatrician. If they approve of the Zipadee, go for it!!
My 4 month old sleeps in a merino wool sleep sack that says it’s suitable from birth to 2 years. The neck hole is small enough that I’m sure his head can’t slip through. However, the sack is obviously very long on him. Is there any danger in your opinion from all the extra length? Thanks
Hi Emma!! I don’t know that I see anything dangerous in it – but I would talk to your pediatrician about your concern with the length just to make sure.
I noticed that you said stop swaddling at 8 weeks or when babies have the ability to roll over on their own, or whichever comes first.
Did you mean to say 8 months, not 8 weeks?
8 weeks is correct.
Hi, is it safe for you to put 2 sleep sacks on your baby? For example, I have to .5 tog sleep sacks and my baby doesn’t have a onesie that will fit under his PJ’s but it is very cold in his room. I have a warmer sleep sack but it’s too warm for the current weather. Can I double up on the sleep sacks and have him wear two to bed?
I’d stick to one sleep sack. Or, check out these sleep bags by Kyte baby that come in different thickness levels. https://kytebaby.com/collections/sleep-bags