Newborn Sleeps With Mouth Open: When You Should Worry

Newborns sleeping with their mouths open is common, but it’s not considered harmless. The best course of action is to consult your pediatrician for tailored advice since online searches will overwhelm you with irrelevant respiratory concerns that may not apply to your loved one.

To put your mind at ease, here’s a quick tip: Gently close your baby’s mouth. If they continue to breathe normally through their nose without gasping, then there’s no cause for concern. You should only worry if they consistently and actively breathe through their mouth instead of their nose.

baby sleep with mouth open

Newborns have underdeveloped oral respiratory systems. Premature mouth breathing has lasting effects such as poor teeth development, underdeveloped facial bones, and speech impediment. The good news is, in almost all cases, parents can resolve the issue before the child is 6 – 7 months old.

Is It Normal For Babies To Sleep With Their Mouth Open?

When it comes to breathing during sleep, the most important factor is tongue positioning. Our anatomy ensures that the tongue is placed on the roof of the mouth when sleeping. This blocks the airways in the mouth, encouraging nasal breathing and discouraging mouth breathing.

We need to breathe through the nose, when awake and asleep, because the nose allows for better oxygen absorption, humidifies the air, and filters toxins to remove dust and allergens. Plus, it keeps the mouth free for feeding, reducing the risk of choking.

In adults, mouth breathing usually causes bad breath and gum disease only since we have fully developed oral respiratory systems. Newborns do not have this privilege as they have underdeveloped oral respiratory systems.

They can’t easily breathe through their mouths until 5 months of age. This means that newborns are not mouth breathers but obligate nasal breathers, they rely solely on breathing through their nose.

So, how come newborns sleep with their mouths open if they are obligate nasal breathers?

Well, their nasal air passages can be congested with mucus or obstructed due to anatomical abnormalities. These problems make it hard for them to breathe through their nose, and they resort to mouth breathing with their underdeveloped systems to get oxygen.

This restriction is not without its consequences.

Risks of Mouth Breathing in Newborns

Proper tongue positioning on the roof of the mouth also provides enough pressure for the upper jaw and teeth to develop properly around the tongue.

Breathing through the mouth means the tongue rests at the bottom of the mouth. Without proper pressure, the upper jaw can’t develop well and this can lead to teeth crowding and narrower facial features.

The risks to their dental health and physique include:

  • Facial deformities, due to improper jaw growth.
  • Long-face syndrome, where the newborn grows to develop an elongated face.
  • Poor mouth posture, due to altered positioning of lips and mouth muscles.
  • Articulation disorders, due to altered airflow and pressure within the oral cavity.
  • Dry mouth and lips, since reduced saliva leads to natural bacteria interference which promotes bad breath, gum disease, and tooth decay.
  • Need for braces, to repair misaligned teeth.
  • Poor sleep quality, due to lower oxygen intake and mouth breathing which contributes to apnea.

Mouth Breathing Vs Newborn Sleeping with Mouth Open

Before getting concerned, it is important to know that a newborn sleeping with an open mouth is not necessarily a sign of mouth breathing.

When infants sleep, their mouths may naturally fall open due to relaxation, but they can still primarily breathe through their noses.

So long as their tongues rest against the roof of their mouths, they are fine! Also, if you close their mouths during sleep and they continue breathing through their nose without gasping, then they are still doing great.

Essentially, sleeping with their mouth open is harmless, but the concern arises when it leads to mouth breathing.

Signs & Symptoms Associated With Newborns Sleeping With Mouth Open

While occasionally sleeping with mouth open during sleep is normal, consistent mouth breathing in newborns should be addressed. Take note of these signs:

  • Thick nasal mucus
  • Snoring, grunting, gasping, or noisy breathing when sleeping
  • Restless sleep
  • Mouth breathing when awake
  • Difficulty feeding, since mouth breathing makes it hard to breathe and feed simultaneously
  • Sniffing and coughing
  • Teeth grinding, especially during sleep
  • Tongue thrusting
  • Dehydrated lips and mouth

7 Reasons Why Your Baby Sleeps With Mouth Open

According to pediatricians, the most common reason is nasal blockage due to stuffy noses from colds or allergies and when their adenoids or tonsils are too big.

Other reasons make these occurrences possible and it is prudent to address each one of them to narrow down the causes:

1. Sleeping Position

Many parents report cases in which newborns sleep fine with their mouths closed while lying on their backs, but they tend to sleep with their mouths open if lying on their chests or being held.

If changing their sleeping position fixes the problem, then they were just uncomfortable or the prior position obstructed their breathing somehow.

2. Prematurity

Babies born prematurely may have underdeveloped systems that can lead to blockages in the nose. They are also almost two times more likely to develop asthma which impairs breathing.

Premature babies are more sensitive to environmental factors such as allergens, dry air, bad weather, and air pollution. All these conditions can prompt the newborn to breathe through their mouth.

Infants under 6 months old, particularly those born prematurely, may have narrower airways, leading to nasal obstruction. This can result in breathing through the mouth. While this often resolves with age, consulting a pediatrician will help speed the process.

3. Mucus Accumulation & Nasal Congestion

Nasal congestion in newborns is often caused by allergies. Other causes include infections (mainly of viral origin), dry air, deviated septum, and air pollutants.

Infections like the cold, flu, and sinusitis can lead to an overproduction of mucus. The mucus blocks the nostrils and instinctively the newborn will start mouth breathing.

Other associated symptoms include: coughing, runny nose, sniffing, noisy breathing, and difficulty feeding.

It is important to address allergies early since some can trigger asthma which will impair nasal breathing further by causing more congestion.

Another possible cause is nasal polyps. These are harmless inflammatory masses that can lead to nasal obstruction. They are rare but when they occur, they block the nose and trigger mouth breathing.

4. Obstructive Apnea

Obstructive apnea is the main type of infant apnea that causes obstructions to the upper airways.

Obstructive apnea is a result of OSA (Obstructive Sleep Apnea) which is a condition when the airways are blocked and the respiratory systems cannot maintain ventilation.

OSA in newborns can be caused by:

  • Underdeveloped respiratory systems
  • Anatomical issues such as having a small jaw (Pierre-Robin Syndrome), enlarged adenoids, or swollen tonsils.
  • GERD (Gastroesophageal Reflux), caused by the reflux of stomach contents into the throat
  • Infections such as pneumonia, croup, and other airway inflammatory illnesses

OSA is mostly caused by enlarged adenoids or swollen tonsils.

OSA’s number one sign is snoring. Other signs include restless sleep, coughs, hoarseness, and pauses between breaths.

5. Lip and Tongue Tie

A tongue tie (ankyloglossia) is a condition where the skin beneath the tongue (lingual frenum) connecting it to the floor of the mouth is tighter than normal. A tongue tie may not cause any abnormalities but in some cases, it can prevent the tongue from reaching the roof of the mouth, leading to mouth breathing.

To see if your newborn mouth breathes because of tongue tie, take note of these accompanying symptoms:

  • Difficulty latching to the breast/bottle when feeding and inefficient milk extraction – this is the most prevalent symptom.
  • Difficulty sticking tongue out past the lower lip. The tongue can also be heart-shaped when stuck out.
  • Restricted movement when moving tongue upwards.

Lip tie is another possible cause, where the skin (labial frenulum) connecting the lips to the gums is tighter than normal. Severe lip-ties can lead to mouth breathing but they are a less likely cause compared to tongue tie.

6. Deviated Septum

A deviated septum is an anatomical issue where the newborn’s nasal septum is abnormally positioned to one side, altering the size of the nostril air passages and thereby restricting airflow.

Some are born with it and others may develop it due to an injury to the nose.

7. Narrower Jaws

An ideal newborn jaw is wide and U-shaped. In some babies, the jaw may come out V-shaped and narrow.

A narrow jaw leads to overcrowding of teeth in the mouth which leaves less room for the tongue to rest on the roof of the mouth, potentially obstructing the nasal passages and promoting mouth breathing.

Diagnosis & Treatments for Newborn Sleeping With Mouth Open: Step-by-Step

The first step is to diagnose if the baby sleeps with mouth open but breathes through the nose. If this is the case then it implies that there aren’t any nasal blockages and therefore, they only require proper breathing training to avoid mouth breathing.

1. Proper Breathing Training

You should close your child’s mouth when they are sleeping. Pediatricians often recommend you train them by gently lifting their chin to close their mouths. Doing this consistently will encourage them to breathe through the nose over time, reducing habitual mouth breathing.

You may also want to change their sleeping position if you notice they sleep with their mouth open in one position but not another.

This method only applies if there are no underlying structural or nose breathing issues.

2. Saline Solution for Nasal Congestion

Look out for the nasal congestion symptoms to apply this method.

The use of saline solutions is a safe and efficient way to clear out the airways and drain stuck mucus. You may also use a bulb aspirator to ensure there isn’t any mucus accumulation.

Proceed to manage illness symptoms in case of infections and wait for the sickness to pass. Do not forget to apply treatments for the underlying infections and allergies.

3. Surgery

If swollen tonsils or adenoids are the cause, your pediatrician will refer you to an ENT who will diagnose and treat the issue by performing a tonsillectomy or an adenoidectomy, or small surgical procedures. The ENT can also diagnose and surgically remove a tongue tie or lip tie.

These are minor and short surgeries with little side effects, a baby can breastfeed immediately.

In the case of a narrow jaw or improperly positioned teeth, your pediatrician may refer you to an orthodontist who will select the appropriate orthodontic surgery to reposition bones or teeth.

Best 6 Preventative Measures To Avoid Mouth Breathing

Prevention is the best cure in the case of mouth breathing:

  1. Maintaining a clean environment through vacuuming to avoid allergies and infections.
  2. Monitor air quality in the baby’s environment.
  3. Breastfeed them as it engages the newborn’s tongue muscles, improving mouth development.
  4. Use the right pacifier and bottles, as improper or prolonged use of pacifiers and bottles can keep the jaw narrow, encouraging mouth breathing.
  5. Supervise the newborn to prevent infections and accidental nasal blockage from objects.
  6. Keep up with regular checkups and treat mouth breathing early before the major adolescent growth spurt when the effects become permanent.

How is Mouth Breathing Linked to ADHD?

Mouth breathing affects sleep patterns leading to poor sleep quality which causes daytime sleepiness, poor focus, moodiness, and other symptoms that are similar to ADHD symptoms.

Mouth breathing should be assessed at an early age to prevent unnecessary exposure to ADHD medication since addressing mouth breathing can heal the symptoms.

Also Read: Why Am I Snoring All of A Sudden?


It’s normal if your newborn occasionally sleeps with their mouth open. However, if they consistently breathe through their mouth, it’s important to seek treatment promptly. Mouth breathing can lead to speech problems, facial development issues, and poor sleep quality that may persist into adulthood.

Although we cannot address all the problems, our Sleep Pilot App provides a way to improve your newborn’s sleep quality to address issues with mouth breathing. By monitoring sleep patterns, Sleep Pilot offers insightful analytics you can use to optimize sleep.

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