When to Stop Using a Sleep Sack for Your Baby

You might never have heard of a baby sleep sack before your babe arrived.

But once you discovered them, you were probably jealous of your baby’s cozy toes!

Sleep sacks are a great way to keep your baby warm and help them to drift off to sleep.

(And in the cutest mini sleeping bag!)

But if you're wondering when to stop using a sleep sack for your babe, well, if they’re happy, you can keep going until they’re just too tall.

As always, there's more to the story, so let's dive in, with the help of baby sleep expert, Alicia Dyshon.

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What is a sleep sack?

When we say ‘sleep sack’, we mean a wearable blanket for your baby to snuggle up in while they’re getting their all-important sleep.

It zips up, and has holes for your babe’s arms and head.

While they’re wearing it, your baby can kick around as much as they like inside the bag, but they can’t kick it off.

Baby sleep sacks come in different sizes and weights – from quilted ones with sleeves for the winter to muslin ones for a heatwave.

Are sleep sacks safe?

Yes, baby sleep sacks are safe, as long as they fit properly, they’re not too heavy for the temperature of the room, and you're following the suggested safe baby sleep guidelines.

In fact, they're often recommended by medical professionals and can help regulate baby's temperature, which could be a contributing factor to SIDS (sudden infant death syndrome).

They're also designed so they're not loose (like blankets) and can't cover baby's face, which has also been linked to SIDS.

Just remember, a sleep sack is not the same as a swaddling blanket, which is specifically designed so that newborns can’t move their arms around and startle themselves awake.

Doctors advise that you should stop using a swaddling blanket as soon as your baby starts to roll over, which can be from 2–3 months.

When should babies stop wearing sleep sacks?

There’s no rule about when to stop using a sleep sack for your babe.

You might choose to keep using it until your little one gets so tall that they don’t have space to stretch their legs out anymore – but even then, there are lots of options for wearable blankets that fit up to the age of three.

Or you might keep using it until your little one learns how to unzip the sleep sack themselves.

(But we hear that lots of parents thwart these particular escape attempts by putting the sleep sack on backward so that the zip is out of reach.)

You could also keep going until your babe graduates to a big-kid bed that they can get into and out of themselves.

If they’re tripping over the sleep sack when they come to find you in the morning, it might be time to upgrade.

Having said that, some companies do make footless wearable blankets, so that your toddler can have the security of a sleep sack while still being able to, well, toddle.

So how long do babies use sleep sacks?

It’s up to your family, and you have a lot of flexibility here.

Unlike getting rid of the swaddle, it’s really not a transition that you have to rush.

When to transition from sleep sack to blanket

If you’re trying to choose your moment, it might be good to hang on to the sleep sack until your toddler is old enough for a blanket.

According to the AAP, it’s safe for a toddler to sleep with a blanket once they turn one, as long as they’re tucked in and the blanket isn’t too big for their bed.

So if you're transitioning from swaddling, sleep sacks can be great, providing them with the warmth and comfort they need to drift off, without the risk of covering their face.

When not to use a sleep sack

Sleep sacks can be a part of your life for your first few years as a parent.

There are just a couple of safety tips to bear in mind.

Don’t use a sleep sack if your baby has a fever

If your baby is sick and has a fever, it’s best not to use their regular sleep sack, because they won’t be able to kick it off if they get too hot.

While they’re unwell, they’ll be fine in just their pajamas.

Choose a sleep sack or a blanket

It’s best not to use a sleep sack and a blanket together.

One or the other is enough to keep your baby warm.

Using both together could mean baby's too warm, which can be dangerous.

Use a sleep sack that fits

Sleep sacks exist so that you don’t have to put loose items in your babe’s crib or bassinet.

But if the sleep sack is too big and they can wriggle down inside while they’re sleeping, it can become a suffocation risk.

So make sure you go for one that’s the right size.

Use a sleep sack with the appropriate TOG rating

Sleep sacks have different TOG ratings (which stands for Thermal Overall Grade), a unit of measurement for insulation and warmth of sleepwear and bedding.

You'll probably see most sleep sacks have a TOG rating ranging from 0.5-2.5.

Simply put, the higher the TOG rating, the warmer the sleep sack.

So you'll want to choose the appropriate TOG rating based on the temperature of baby's sleep environment.

Baby sleep expert, Alicia Dyshon, says, "If the temperature warms up and you’re moving into summer time heat, you won’t want to be using a sleep sack with 2.5 TOG rating" — that's more for winter-time baby sleep to keep them snuggly.

Let's be honest, figuring out when to change baby routines can be a little nerve-wracking, right?

Well, you're not alone, mama!

There's a whole community of moms like you on Peanut, sharing their stories and experiences — everything from fertility and pregnancy to baby sleep, toddlerhood and beyond!

So if you're after more advice on when to stop using a sleep sack for your babe, or you want to connect with other moms just like you, join us on Peanut.

We think you'll fit right in.