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Why Do Newborn Babies Smile In Their Sleep?

As a Wiltshire newborn photographer, I love nothing better than capturing beautiful newborn smiles for my clients! And of course, every parent of a newborn is thrilled to have a beautiful, smiling photograph of their baby. However is something mysterious about these sleepy smiles and they are certainly not guaranteed. Some babies just seem to be very smiley, while others don't smile at all during their newborn photography session. So I wanted to investigate further - why do some newborn babies smile in their sleep?

Smiling newborn baby girl; Salisbury newborn photographer, Rachel Burnside

The 'Windy' Smile - An Old Wives Tale?

Let's start with the traditional explanation for newborn smiles - passing wind. Or let's not be shy about it, I'm sure at some point someone will have told you with great authority that newborn babies smile when they fart! It might not surprise you to learn that there is no actual scientific evidence to support this theory, although to be fair I can't find a single study that has tried. The thinking behind it is that perhaps your baby has a pain in their tummy caused by wind and then are smiling at the pleasant feeling when it is released. Understandable perhaps! Slightly more credible is the idea that when newborn babies have pain from trapped wind, it can make their muscles tighten around their face and they will grimace, which often looks like a little grin.

Cute newborn baby smiles captured by Wiltshire newborn photographer, Rachel Burnside

Is The Newborn Smile Just a Reflex?

The newborn smile reflex is present even before your baby is born, from about 33 weeks gestation. So, if you're very lucky, you might even catch on of their smiles in your scan photo! These smiles are called endogenous smiles and are caused by a reflex, much the same as the thumb sucking which is seen inside the womb. These reflex smiles continue after birth and could be your baby's way of practicing using their facial muscles, ready for those 'real' social smiles that will come later. Reflex smiles are not voluntary and are not a response to any external stimulation, they're just inbuilt reflex movements much like sucking and kicking.

Wiltshire newborn photographer; Smiling newborn photographs

Why Do Newborns Smile More in Their Sleep?

Most of the newborn smiles I capture during newborn photography sessions happen when babies are asleep. Much like adults, babies go through different phases of sleep - REM and Non-REM. REM sleep is also called active sleep and it is the time when we as adults or older children experience dreams. The brain has activity similar to when we are awake and the eyes will often flutter beneath the eyelids. Baby's also experience REM sleep and will twitch, flutter their eyelids or roll their eyes and often smile. As a newborn photographer, always on the look out for that precious newborn smile, these signs of baby entering the REM phase of sleep are my cue to have my camera at the ready.

Why do newborn babies smile in their sleep?

Do Newborn Babies Smile in Their Sleep Because They Are Dreaming?

It's possible that newborns may experience dreams during the REM phase of sleep just as children and adults do. However, there has been very little research into this area, so no-one knows for sure. Many experts point out that because our dreams come from past experiences and emotions, newborns are unlikely to experience dreams in the same way as their emotions and brains are not yet as developed. It is therefore thought unlikely that sleepy newborn smiles are because of pleasant dreams, but who knows! Maybe they're dreaming about milk and cuddles.

Beautiful smiling newborn by Rachel Burnside newborn baby photographer

Do Babies Laugh In Their Sleep Sometimes?

Believe it or not, babies sometime laugh and giggle in their sleep too! It's usually slightly older babies rather than newborns and they can let out quite a chuckle. Quite a surprise it you're not expecting it and wonderful to capture on video it you're lucky enough to be there at that moment.

Rachel Burnside Newborn Photographer

When can I expect my newborn baby to give me a real smile?

A 'real' smile is a social and responsive smile, rather than just a reflex which your baby has no control over. Responsive social smiles will be seen when your baby is awake and interacting with you, not when they are asleep. You'll probably notice your newborn's first social smiles from 4-6 weeks onwards, although it can be hard to tell at first. By 2 months old, most babies are smiling away in response to your smiles and interactions. They will most likely also continue with those reflex smiles in their sleep too.

Smiling newborn photography; Rachel Burnside Photography

So Why Do Newborn Babies Smile When They Are Asleep?

The answer is that no-one is 100% sure why even tiny newborn babies smile while they are sleeping. There has been very little research into newborn smiles, however most experts agree that the most likely explanation is that newborns have the smile reflex from before birth and sometimes it happens when they are in the REM or active phase of sleep. Passing wind or having sudden relief from an uncomfortable tummy may also have something to do with it, but it's not been scientifically proven. Whatever the reason, just enjoy those gorgeous sleepy newborn smiles while they last! The real thing will happen soon enough and when it does, you'll know the difference.


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