What do newborn babies sleep in!?

While researching what clothes needed for a baby, it can become very confusing. Does a baby need pants, or skirts? Does a baby wear anything under their swaddle? How do you know if they are warm or comfortable? These are all tough questions to answer. My research went many directions and I will try to give you some thoughts on how to decide what sleep wear to buy.

What are the different outfits?

The main pieces of clothing you need are called onesies. Onesies might also called undershirts or sleepsuits! These are all the same thing. Sleepsuit is the generic name. The main thing to think about then for the outfit is do you want to have sleeves and legs. These are all personal preference, but I think almost certainly you want to have some that cover the foot. Ideally, you may find some that cover the hands as well, but these are hard to find. Some that cover less and some that cover more will give you some flexibility.

What accessories are safe?

Because of SIDS (Sudden Infant Death Syndrome), you want your baby to sleep with almost nothing else except for the onesie! The onesie also needs to be reasonably tight fitting so that it is not too baggy and can get into the baby’s mouth area or for the baby to slip out of it. Don’t worry too much if it is not form fitting though, babies grow fast!

Accessories wise, you might have mittens or booties or hats in your wardrobe, but your baby should NOT sleep in them! They are at risk for SIDS with these items. You should also make sure your onesies do not have buttons or other small parts.

Diapers however are of course recommended to wear while sleeping!

What about swaddling?

Depending on your preference, your newborn baby can sleep with their clothes under their swaddle, or not wear clothes under their swaddle, or not wear a swaddle at all (probably with clothes). You can also try to wear a swaddle transition sack. Any way is fine, so see how your baby is feeling and do what makes them feel the best. Swaddling has slight links towards development issues in the baby’s hips, so do not keep them swaddled all day, and if the baby does not like the swaddle, then it isn’t needed!

How to tell what the baby likes?

This is more of a mystery because it is different for every baby. Hopefully you can build a connection with your baby and be able to tell what they like and don’t like! They might have similar or different personality to you. There are different cues, like if the baby cries, or they try to struggle out of their clothes.

I would also see if the baby is feeling hot or cold. You can feel them, you can measure their temperature, or again, see how they are feeling and see what elements might be causing them to feel a certain way. Your sleeping environment should have a way to measure the temperature and you would want it to measure 68 degrees fahrenheight to 72 degrees fahrenheight.


Usually baby clothes come in preemie, newborn, 0-3 months, and then further out. The main question is, do you buy newborn clothes? Baby clothes is mostly designed for certain weights. This is a big concern because you won’t know how big your baby will be born at! And very quickly newborns will usually start fitting the 0-3 months clothes, but what do they wear for the first week or so when they are less than 8 pounds? As noted above, you do not want your baby in too loose fitting clothes. If you are willing to wait it out, you can see and then buy, but that is too last minute for me. I decided to put a few newborn outfits on the list and then if it becomes a necessity, I can then buy more but have a few that make due. Most people simply get some clothes from their friends if needed, or you can use the 0-3 month pieces earlier and hope the baby grows into them while keeping an eye on them to see if the clothes is too loose.


What you dress your baby in when they sleep is mostly up to the baby! As such, I recommend you buy a variety of different options. However, do not let your baby sleep in loose clothing or articles that may cause SIDS. Hope you have a happy sleeping newborn baby!

Here are some of the clothing pieces we decided to go with!

Want more information about taking care of a newborn or caring for your baby? Check out these articles about a class on newborn babies!

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