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Is It Normal for My Newborn to Sleep With Their Mouth Open?
Back to Baby Sleep
You're doing the 3am breathing check (for the fourth time), and there it is: your newborn, fast asleep, mouth wide open like they're mid-yawn. Adorable? Absolutely. Normal? Usually, yes. Here's why babies sleep with their mouths open, what can cause it, the signs worth a call to your pediatrician, and simple ways to help your little one breathe comfortably all night.
The short answer
Most of the time, yes. A newborn sleeping with their mouth open is often just a relaxed jaw, a sleepy, milk-drunk baby or a stuffy nose. Newborns much prefer breathing through their nose, so if your baby breathes through their mouth most nights, snores loudly, or seems to pause or struggle when breathing, it's worth checking in with your pediatrician.
Why Newborns Sleep With Their Mouths Open
Newborns are natural nose breathers. In the early weeks, breathing through the nose is their strong preference, and it's how their little bodies are set up to breathe best.
So why the open mouth? Often it's simple relaxation. Once your baby drifts off, their jaw muscles soften and their mouth can fall open, especially after a big feed. Plenty of babies nod off mid-feed and stay in latch position long after the milk has stopped. Others are just a bit snuffly. Newborn nasal passages are tiny, so even a little mucus can make nose breathing harder work.
The occasional open-mouthed snooze is nothing to stress about. It's when mouth breathing happens most nights, alongside other signs, that it's worth a closer look.
When Do Newborns Breathe Through Their Mouth?
Newborns can breathe through their mouths when they need to, like when they're crying or their nose is stuffed up, but given the choice they'll use their nose. Between about 4 and 6 months, as their airway grows and changes, babies start to breathe through their mouths more easily too. By around 12 months, their breathing pattern is much closer to yours.
Common Reasons And Causes
Most of the time, a baby sleeping with their mouth open has a simple, harmless explanation. Common causes include:
- A stuffy nose. Colds and mucus can make nose breathing tricky, so your baby switches to their mouth for a while.
- A relaxed jaw. Once your baby is asleep, their muscles soften and their mouth can naturally fall open.
- Dozing off during a feed. Babies who fall asleep at the breast or bottle often stay open-mouthed for a little while after.
- Allergies. Ongoing allergies can keep the nose congested, even without a cold.
- Enlarged adenoids or tonsils. These soft lumps of tissue at the back of the nose and throat can narrow the upper airway. They're a more common cause in toddlers and young kids than in newborns.
- The shape of their airway. Occasionally, the structure of a baby's face or airway makes nose breathing harder. Your pediatrician can take a look if you're unsure.
Even when there's a reason behind it, mouth breathing on its own usually isn't harmful. It's still worth keeping an eye on, especially if it hangs around after a cold has cleared.
When To Be Concerned About Mouth Breathing And Baby Sleep
You know your baby best, so trust your instincts. Call your pediatrician if your baby:
- Breathes through their mouth most nights, even without a cold
- Snores frequently or loudly
- Has pauses in breathing, or seems to gasp, choke or snort in their sleep
- Is very restless or sweaty when sleeping
- Finds feeding hard work or tires quickly during feeds
- Seems unusually sleepy during the day
According to the American Academy of Pediatrics (AAP), frequent snoring and breathing that stops and starts during sleep can be signs of sleep apnea. Short pauses followed by a few quick breaths can be a normal part of newborn breathing (called periodic breathing), which usually settles by around 6 months. If you're unsure which you're seeing, your pediatrician can help, and sleep apnea is treatable.
Call 911 if your baby stops breathing for more than 20 seconds, or their skin looks pale, bluish or grayish. Call your pediatrician right away if your baby is having trouble breathing or breathing fast, or is under 3 months old and has a fever.
Tips To Help Babies Breathe Comfortably While Sleeping
A few small habits can help your baby breathe easy, day and night:
- Keep their nose clear. A drop or two of saline in each nostril can loosen mucus, and a bulb syringe can gently draw it out. Over-the-counter cough and cold medicines aren't recommended for children under 4.
- Go gently with feeds. A stuffy nose makes feeding hard work, so your baby may take smaller feeds and wake sooner. Clearing their nose before a feed can help, and give them plenty of little breaks.
- Always put them to sleep on their back, on a firm, flat surface. It's tempting to prop up a congested baby, but the AAP recommends a flat, non-inclined surface for every sleep, and advises against routine sleep in car seats, swings and other sitting devices. Our safer sleep guide covers the basics.
- Keep the crib bare. No pillows, blankets or soft toys, so their face stays clear and air can flow freely.
- Keep their sleep space smoke-free. Smoke can irritate little airways, so keep it (and vaping) well away from your baby.
- Dress for the room. Aim for comfortably warm, not toasty. Feel their chest or the back of their neck to check, and see our guide to signs your baby is too hot or cold.
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FAQs About Babies Sleeping With Their Mouth Open
Is it bad for my baby to sleep with their mouth open?
Usually not. An open mouth during sleep is often just a relaxed jaw or a stuffy nose. If your baby breathes through their mouth most nights, snores loudly, or seems to pause or struggle when breathing, check in with your pediatrician.
What can I do if my baby's nose is frequently congested?
Try a drop or two of saline in each nostril and a bulb syringe to gently clear mucus, especially before feeds. Keep putting them to sleep on their back on a firm, flat surface. If their nose is often stuffy even without a cold, or it's getting in the way of feeding or sleep, see your pediatrician, as allergies or enlarged adenoids can be behind it.
Can mouth breathing affect my baby's development?
Occasional mouth breathing won't. When it's linked to ongoing sleep problems like sleep apnea, untreated broken sleep can affect a child's attention, behavior, learning and growth. That's why persistent mouth breathing is worth getting checked. The good news: the causes are usually treatable.
Is it normal for my baby to snore?
Light, snuffly snoring is common, especially when your baby has a cold. Frequent or loud snoring, particularly with mouth breathing, gasping or pauses in breathing, is worth a call to your pediatrician.
Should I close my baby's mouth while they sleep?
No need. Gently closing their mouth won't change how they breathe, and you should never use anything that covers their mouth or face. Simply lay your baby on their back on a firm, flat surface with nothing else in the crib. If the mouth breathing continues, ask your pediatrician.
Key takeaway
A newborn sleeping with their mouth open is usually just a relaxed, sleepy baby or a stuffy nose. Keep their nose clear, always put them to sleep on their back on a firm, flat surface, and dress them comfortably for the room. If mouth breathing happens most nights, or comes with loud snoring, pauses in breathing or tricky feeds, check in with your pediatrician. You know your baby best.
Looking for more sleep support? Explore our baby sleep blog for expert tips from newborn days to big kid beds.