Dressing Your Baby For Sleep

Dressing your baby for sleep is one of those things that seems pretty straight forward- that is until you have a baby. Suddenly you realize there’s so many options and things to consider. Do I get the snaps or the zipper? Do I need organic fabrics? Are they too cold? Grandma says they need a hat, doctor says they don’t… What to do?!!

In this blog, I’m breaking down some of the science to help you figure out options around sleep.

Sleepwear and Safety

Whenever we’re talking about our babies and sleep, safety should be the first consideration. There’s a few things I want to discuss in this area.


Studies have shown that overheating can increase the risk of Sudden Infant Death Syndrome. We don’t know the exact ideal temperature and amount of clothing that is right. Really, it would be impossible for people all over the planet to control their infant’s temperature exactly. But we do know that overheating can cause babies to sleep too deeply and possibly not wake.

On that note, the AAP recommends NOT using a hat on your baby indoors. This is a common thing parents do first thing because their baby’s head seems so fragile- but please know it could contribute to overheating.

When it comes to checking a baby’s temperature, feeling the back of their neck is one of the best ways to gauge how they are feeling. Parents often believe their infants are cold because their hands and feet feel cold. But remember that infants do not have great circulation yet so it’s normal for their extremities to be cold. Although grandma might recommend mittens, it isn’t always necessary. In fact, babies learn a lot through feeling with their hands and many studies have found it beneficial for babies to have access to their hands.

Later in this blog we will talk more about choosing clothes for the temperature. For now, just remember that cold isn’t ideal but overheating is most dangerous.

Small baby sleeping cozily in a short sleeved onesie.


Swaddling is a hot topic and one that requires its own post. For now, I just want you to be aware that if you choose to swaddle, there are safety considerations to keep in mind:

  • There should never be extra fabric around baby’s head or neck
  • Hips and legs should have space to move to prevent hip dysplasia
  • An infant should never be swaddled when bedsharing
  • As soon as you see signs of rolling or ideally by 8 weeks of age, it’s time to transition out of the swaddle

A sleep sack where the arms are free is fine and great to use well into toddlerhood. We just want to make sure a baby has access to their arms and hands to prevent them getting stuck in a compromised position.

It’s also important to note that babies use their hands to help them with breastfeeding. They might push on the breast, for example, to help the flow of milk. Ideally babies should be unswaddled when breastfeeding- please discuss further with your lactation consultant.

Weighted Sleep Sacks

Weighted sleep sacks have become really popular in sleep training circles. Brands like the ‘Magic Merlin’ promise to help your baby sleep better when transitioning from swaddling. And some even have chest pads that add extra weight. The AAP, however, cautions against these as they could increase the risk of entrapment and overheating.

Now, here’s the thing: weighted sleep sacks CAN be helpful for sleep just as weighted blankets are for adults. That’s because it can be a helpful tool for those who might have sensory sensitivities. My professional preference is to only use these under the advice of an Occupational Therapist or Physician. Only a qualified professional can tell you what the right weight is and how to use it safely.

Newborn baby sleeping in a swaddle

Fabric choices

Fleece is a common and popular fabric choice for winter gear. However, fleece being a synthetic fiber is not a very breathable fabric and it can increase the risk of overheating.

Opt, as much as possible, for natural options like 100% cotton or wool. If you need to layer up, adding layers of cotton is better than fleece. Wool, although harder to find at an affordable price, is extremely efficient at maintaining a good body temperature so it’s a fantastic choice if you need something for cold nights.

Loose bedding or hoodies

As you probably know already, any loose bedding is not ideal where the baby is sleeping. Keep their sleep space free of pillows, blankets, and stuffies until at least their first birthday. Hoodies on clothing are also not ideal as they could get tangled up when the baby moves and cause strangulation. One idea for daytime naps is to simply take off most of their clothing and leave them in their onesie and then add a sleep sack on top.

Comfort and Ease

Let’s make sure your baby is feeling cozy and we make life easier for YOU.

Snaps vs zippers

You might have seen lots of memes onlines about parents telling you to ‘get the damn zippers!’. They’re not wrong- zipper pj’s, especially ones that zip from top or bottom are much easier to use for those middle of the night diaper changes.

That said, snaps aren’t totally useless. For example, if your baby is in the NICU and they have monitors strapped to them, a snappy PJ can be really helpful. So don’t completely discount them! But yeah, if your baby doesn’t need the snaps you’ll probably prefer the zips. 

How Warm Should the Sleep Space be?

What we know is that generally humans sleep best when their house is cooler at night than during the day. According to the National Sleep Foundation, the ideal room temperature for infants to sleep in is around 69°F/20.5°C.

That said, I would be remiss to point out that this is just not possible for all families to achieve. For starters, not all families have access to indoor heating or climate control, let alone being able to choose a specific temperature they want inside. So we need to be realistic with managing temperature.

The other thing I like to point out is that just like all adults prefer different temperatures, the same goes for babies! For example, I’ve worked with clients in Arizona who looked at me like I had 3 heads when I mentioned that 20.5 degrees is considered ideal. For them, this is way too cold, not to mention expensive to get their house that cool. Because their bodies are used to the Arizona heat, 24-25 might be a very comfortable inside temperature- whereas my Canadian self would feel like I’m about to melt. So remember that when you come across guides online- we all feel temperature differently and the important thing is how YOUR baby feels.

Having a fan going in the bedroom is almost always a good idea. It helps circulate the air and prevent hot pockets. The noise can also help drown out outside noise and become a sort of white noise for baby.

In dry winters, I often recommend a cool-mist humidifier. This doesn’t change the temperature per se, but it helps make you more comfortable in your sleep space. It can help a lot if baby experiences chronic congestion as well.

TOG rating and sleep sack charts

TOG stands for Thermal Overall Grade and it’s the preferred measure used by sleep sack companies. You will notice most sleep sacks have a TOG rating somewhere- usually ranging from 0.3TOG (for light summer sleep sacks) and 3.5TOG (for thicker winter sleep sacks).

Sleep sack companies often offer charts to help you know how to dress your baby under their sleep sacks. Here’s a couple examples:

Again, these can be a really helpful tool. What I always urge you to remember is that everyone responds to temperatures differently. For example, it’s about 20°C in your home and you have your baby in a 3.5 TOG sack with a long sleeve sleeper underneath. According to the chart by Ergo pouch this would be perfect. But say you are finding your baby is always waking up sweaty and/or they feel hot to the touch. Then please don’t just go by the chart! Go ahead and use a lighter pj or a lighter sleep sack and see how they do.

Are there signs a baby is cold or hot?

While checking their body is the best way, there might be some clues that your little one is too hot or too cold at night


A lot of infant sleep advice doesn’t take into account bedsharing. But it’s a reality that parents are bringing babies into bed and with more research, organizations like the NHS are updating their safe sleep recommendations.

When it comes to temperature, I urge you to consider if your baby is bed-sharing some of the time. What I often find is that a baby who is bed-sharing struggles to sleep in their own space due to being cold. Don’t get me wrong, they want to be close to you for a million reasons. But this is one that can easily be modified. 

Consider that when your child is in your bed you are providing body heat. And when they are away from you that is missing. One good sign of this is that they wake often and want to stay close to you for cuddles, even if they don’t need nursing or other soothing. So my rule of thumb is to add an extra layer when the baby is sleeping alone. This could just look like taking off their sleep sack when they come to your bed.

Mom and baby bed sharing safely


Like everything else baby sleep, it’s important to understand the science but also trust your gut! You might even get pushback from family members. My son was born in early summer and our apartment did not have AC. That means he was often hanging out in just a diaper. My mother in law often made remarks about this and I just smiled and nodded. It’s hard to get people out of the mindset of bundling babies up but I knew that he was comfortable and bundling wouldn’t make sense for him in that moment. So don’t be afraid to push back!

Anyways, if baby sleep is becoming difficult or stressful for you and you don’t want to sleep train I am here to help! Check out my coaching services for 1:1 support. And see my Podia site for lots of affordable webinars, guides, and courses.

Let me know what topic you want me to tackle next!

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