You notice it during nap time.
Your baby’s mouth is open. Breathing sounds a little loud. Maybe she snores slightly, or her lips never quite seem to close when she’s relaxed.
And something in you wonders: Is that normal? Should she be breathing through her nose?
The answer to that second question is yes nasal breathing is how babies are designed to breathe. And when a baby is consistently breathing through her mouth instead, it’s worth paying attention to.
Not because it means something is terribly wrong. But because early awareness can make a big difference.
Let’s talk through what mouth breathing actually looks like in babies, what causes it, and when to reach out for support.
Why Nasal Breathing Matters for Babies
Babies are obligate nasal breathers — meaning they’re designed to breathe through their nose, especially in the early months of life.
Nasal breathing:
- Filters, warms, and humidifies the air before it reaches the lungs
- Produces nitric oxide, which supports immune function and oxygen absorption
- Supports proper jaw and facial development
- Keeps the tongue resting in the correct position (up against the roof of the mouth)
- Supports sleep quality and sleep architecture
When a baby breathes through their mouth habitually instead, those benefits are reduced and over time, mouth breathing can affect development in ways that are subtle at first but meaningful later.
Signs Your Baby May Be Mouth Breathing
Mouth breathing in babies doesn’t always look obvious. Here’s what to watch for:
Mouth Is Frequently Open at Rest
This is the most visible sign.
When your baby is relaxed sleeping, resting in your arms, sitting quietly. Does her mouth hang open?
Lips that are consistently parted, even when baby is calm and not crying, can be a sign that nasal breathing isn’t happening the way it should.
Loud or Noisy Breathing During Sleep
Some baby breathing sounds are normal newborns especially can be quite noisy breathers. But consistent snoring, rattling, or mouth breathing sounds during sleep are worth noting.
This is different from the occasional congestion that clears up after a few days.
Snoring or Noisy Sleep
Habitual snoring in babies and toddlers more than just occasional congestion can be associated with mouth breathing and is worth discussing with your provider.
Chapped or Dry Lips
Saliva and air passing over the lips during mouth breathing can leave them dry and chapped — even in babies who are well-hydrated.
Tongue Resting in the Bottom of the Mouth or Protruding Slightly
When a baby breathes through the nose with the mouth closed, the tongue naturally rests against the roof of the mouth. This is called the correct tongue rest posture.
When a baby is a chronic mouth breather, the tongue drops to the floor of the mouth or protrudes forward and this can affect how the jaw and palate develop over time.
Difficulty Latching or Sustaining a Latch During Feeding
Babies need to breathe during feeding. If nasal passages are congested or partially blocked, a baby may struggle to sustain a latch because they can’t breathe and feed at the same time.
This can look like:
- Coming on and off the breast frequently
- Clicking sounds during feeding
- Gassiness from taking in air
- Short feeds followed by fussiness
Restless Sleep or Frequent Waking
Babies who aren’t breathing efficiently during sleep often don’t sleep as deeply or restfully. If your baby seems to startle awake frequently, seems overtired despite sleeping, or is a consistently restless sleeper, this is worth considering.
What Causes Mouth Breathing in Babies?
There’s rarely just one cause. Some of the most common reasons babies breathe through their mouths include:
Nasal Congestion
The most common cause and often temporary. A cold, seasonal allergies, or environmental irritants (dry air, smoke, pet dander) can block nasal passages and force mouth breathing.
When it clears up and mouth breathing stops, there’s usually nothing more to investigate.
When congestion seems persistent or chronic, it’s worth looking deeper.
Enlarged Adenoids or Tonsils
Adenoids are small glands at the back of the nasal passage. When they’re enlarged, they can partially block the airway and make nasal breathing difficult.
Tonsil enlargement can contribute to similar challenges and affects sleep quality particularly.
Both of these are worth discussing with your pediatrician if mouth breathing is ongoing.
Tongue-Tie
This one surprises many parents.
When a baby has a tongue-tie, the tongue can’t lift and rest properly against the roof of the mouth. That low tongue posture can affect:
- How the palate develops (a high, narrow palate can make nasal breathing harder)
- The baby’s ability to seal the lips at rest
- The overall pattern of how the baby breathes
Tongue-tie is often an overlooked piece of the mouth breathing puzzle especially when it’s not causing obvious feeding problems.
Structural Differences
Some babies have small nasal passages, a deviated septum, or other structural factors that make nasal breathing harder. These are less common but worth knowing about.
Why This Matters Beyond Infancy
Mouth breathing that’s addressed early tends to have better outcomes than mouth breathing that becomes a long-term pattern.
Over time, chronic mouth breathing can be associated with:
- Changes in facial and jaw development — the palate may become higher and narrower, the jaw may develop differently
- Dental changes — crowded teeth, open bite, or other alignment issues
- Sleep-disordered breathing — poor sleep quality that affects mood, behavior, and development
- Speech challenges — tongue placement affects articulation; a low-resting tongue can affect how certain sounds develop
- Difficulties with feeding transitions — how a baby manages food textures and eating can be affected by tongue posture and oral motor function
None of this is meant to alarm you. It’s meant to help you understand why noticing these signs early and getting support is a gift you give your child.
When to Seek Support
You don’t need to wait for a crisis. Reach out if you notice:
- Your baby’s mouth is consistently open at rest
- Mouth breathing has been present for more than a few weeks (beyond a typical cold)
- Sleep is consistently restless or noisy
- You have concerns about feeding alongside breathing
- Something in your gut says this is worth a closer look
The earlier these patterns are identified, the more options there are to support your baby gently.
What Support Can Look Like
Depending on what’s contributing to your baby’s mouth breathing, support might include:
- Evaluation for tongue-tie — if oral function and tongue posture are contributing
- Pediatric referral — for adenoid or tonsil evaluation if airway obstruction is suspected
- Myofunctional therapy (MYO) — exercises and strategies that support nasal breathing, correct tongue posture, and lip seal
- Allergy or environmental management — addressing congestion triggers
- Feeding therapy — if oral motor function is affecting both feeding and breathing
You don’t need a diagnosis to reach out. An evaluation can help you understand what’s actually happening and what, if anything, needs to be addressed.
How I Can Help
As a Speech-Language Pathologist and Lactation Consultant, I look at feeding and oral function as a whole picture.
When a baby is mouth breathing, I want to understand:
- Is there a tongue-tie or oral restriction involved?
- Is this affecting feeding?
- Is tongue posture or oral motor function part of the picture?
From there, I can help you understand your options — and connect you with the right providers if additional evaluation is needed.
I serve families in Brownsburg, Avon, Plainfield, Zionsville, and the westside of Indianapolis. And I offer in-home visits so you don’t have to navigate this alone in a clinical waiting room.
👉 Book a free consult to talk through what you’re seeing
👉 Learn more about the support I offer
Frequently Asked Questions
Is it normal for babies to breathe through their mouths?
Occasional mouth breathing during a cold, for example is normal and temporary. But habitual mouth breathing, where a baby consistently breathes through their mouth at rest and during sleep, is not ideal and is worth investigating. Babies are designed to be nasal breathers, and consistent mouth breathing can affect development over time.
How can I tell if my baby is breathing through their nose or mouth?
The easiest way to check is to observe your baby when they’re calm and relaxed during sleep or quiet awake time. If their lips are consistently parted and you can hear or see air moving through the mouth, that’s mouth breathing. A baby breathing through the nose will typically have lips gently closed and breathe quietly.
Can a tongue-tie cause mouth breathing?
Yes. A tongue-tie can affect where the tongue rests in the mouth. When the tongue can’t lift properly due to a restricted frenulum, it may rest low at the floor of the mouth instead of against the palate. This low tongue posture is associated with mouth breathing and can affect how the palate and jaw develop. If mouth breathing is present alongside feeding challenges, a tongue-tie evaluation is often worthwhile.
What is myofunctional therapy and can it help my baby?
Myofunctional therapy (MYO) involves exercises and techniques that support correct tongue posture, nasal breathing, and lip seal. For babies and young toddlers, this is often gentle and play-based. It can be helpful alongside other interventions like addressing a tongue-tie or treating nasal congestion to support nasal breathing patterns. As an SLP, I incorporate myofunctional principles into feeding and oral motor support.
At what age should I be concerned about mouth breathing?
Any age. Even in newborns, consistent mouth breathing beyond temporary congestion is worth mentioning to your provider. The earlier patterns are identified, the more options there are for gentle, effective support. You don’t need to wait until your child is school-aged to address this.
You’re Not Overthinking This
Watching your baby breathe. Noticing how she sleeps. Paying attention to the small things.
That’s not anxiety. That’s motherhood.
And when something catches your attention when something just feels off that’s worth listening to.
You know your baby better than anyone.
