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Baby’s Mouth Is Always Open : What Can Parents Do to Fix Open Mouth Posture in Babies?

Newborn babies are still in their development stages, so there is no shortage of changes that parents may notice as time goes on.

However, if your baby has an open mouth position that doesn’t seem to go away, there could be several underlying causes.

Whether you’re a first-time parent or you’ve had children in the past, you may wonder why your baby’s mouth is always open.

This type of open mouth posture may cause worry and confusion, so read on to learn more about what may cause it and what you can do to correct it.


  1. Open mouth posture definition
  2. Open mouth resting posture throughout the day
  3. While Sleeping
  4. Tongue-Tied babies
  5. Is drooling a sign of autism?
  6. Moebius Syndrome
  7. What can parents do?

What is Open Mouth Posture?

You may start to notice that your baby’s mouth seems to be permanently open, and it’s very rare that their mouth is closed.

If your little one is breathing through his or her mouth and rarely through the nose, they may have an open mouth posture issue.

There can be several different causes for this problem that can range from feeding habits or allergies to something more severe.

If your baby’s mouth is always open and doesn’t seem to close, a visit to the pediatrician is recommended.

The cause of open mouth posture can vary depending on a number of things like genetics, habits, or environmental factors.

In order for parents to determine the cause and find a solution, a healthcare professional will need to make a diagnosis for the root of the problem.

If your baby has an open mouth posture that seems consistent, there’s no need to panic.

Fortunately, there are some things you can do to help remedy the problem with a little bit of practice and care.

Your little one may have an open mouth during the day only, or your newborn sleeps with their mouth open.

Each of these is caused by different habits that you can correct with a few simple changes.

Open Mouth During the Day

If you see that your baby constantly has their mouth open when they play or eat, it’s likely due to a few habits that can easily be changed.

When newborns are in the development stage, they need to begin working on strengthening the jaw muscle and tongue.

Babies that suck their thumbs will develop an oral posture that encourages the mouth to remain open.

Try to encourage your child not to suck their thumb so that their mouths are “trained” to stay closed.

Another cause for open mouth posture during the day is when children are consistently fed food with a smooth texture.

Of course, newborns will only be able to eat food like this but as your child grows, start working on building up to denser foods.

As children begin to eat food with more texture, they build up the muscles of their jaw which can help the mouth stay closed.

Make sure your child is eating on the right schedule, and that they are graduating toward “crunchy” foods or food they need to chew when they’re developmentally ready.

Another common culprit of open mouth syndrome during the day is sippy cups.

When children use sippy cups, they lower their jaw and part their lips too far apart, resulting in a “stuck” open mouth posture.

Try to encourage your child to drink from a regular cup when it’s time, which encourages the jaw to start pulling upward and building muscle.

One way you can start good habits young is to teach your child to chew on flexible, firm objects.

These chew toys help exercise the muscles of the jaw, encouraging it to pull upward so the mouth stays closed.

Over time, this becomes a natural movement that teaches your child to pull their jaw up and activate the lips.

Open Mouth While Sleeping

If it seems as though your baby’s mouth never closes while they sleep, there are many reasons this could occur.

Make sure your child has healthy humidity levels in their room and that they don’t have any known allergies.

It’s important to make sure that your baby sleeps with their mouth closed as often as possible.

Sleeping with an open mouth can cause a dry mouth and lips, and may even make symptoms of asthma worse.

If your newborn sleeps with their mouth open, they may have a cold, asthma, or allergies. Pay a visit to your pediatrician so they can determine if any of these are the cause.

Some babies may breathe with an open mouth in the womb, and this habit simply carries on after they’re born.

Another common cause could be that your newborn has a deviated septum, which is when the cartilage and bone in the nose collapses.

To make up for this, the baby will start to breathe through the mouth.

One other very common reason why babies sleep with their mouth open is if they’re constantly using a pacifier or sucking their thumb.

Try to keep pacifier use to a minimum, and encourage your little one not to suck their thumb whenever possible.

If allergies, a head cold, and asthma are ruled out, try a humidifier in the room.

You can also gently elevate your baby’s head as they sleep to encourage their mouth to close naturally.

Tongue-Tied Babies

A condition called tongue-tie occurs at birth and is caused by a short, thick, or tight section of tissue connected to the bottom of the tip of the tongue and the floor of the mouth.

This may cause your little one to have an open mouth position.

When a baby has tongue-tie, they may have problems eating, speaking, or swallowing. In many cases, a simple surgery can correct this problem.

So how do you know if your baby is tongue-tied? Most newborns will have a difficult time lifting their tongue or moving it from side-to-side.

They may also have trouble sticking their tongue out past their lower front teeth.

In some newborns, the tongue may appear to be notched or heart-shaped whenever they stick it out.

Many mothers will notice that their newborn has trouble breastfeeding or bottle feeding, which could be another sign that your baby is tongue-tied.

Some children might not exhibit symptoms until they get older. If your child has trouble speaking or issues with eating, see your doctor as soon as possible.

Tongue-tie tends to affect boys more often than girls, and it’s usually genetic.

An examination by your baby’s doctor can determine if your child is tongue-tied, and they will make recommendations on how to correct it.

The most frequently-used method to correct tongue-tie is a simple surgical procedure.

After the surgery, your child should have an easier time eating and the visible signs of an open mouth posture should subside.

Is it Autism When My Baby’s Mouth is Always Open?

When dealing with babies who have a consistent open mouth posture, it’s important to note that autism could be another underlying cause.

If your baby seems to drool more than normal, that does not always mean it’s related to autism.

It’s rare for children to be diagnosed with autism and there’s no need to worry too much if you think this could be the issue.

While most babies with open mouth posture have allergies or it’s caused by bad habits like sucking their thumbs, it’s still a good idea to get your child checked out if you’re concerned.

Feeding and sensory problems are two ways parents can observe their children in order to find out if they may have autism.

If your little one refuses to eat, is an extremely picky eater, or they’re having trouble chewing or swallowing, have them examined as soon as possible.

Babies who refuse to eat foods of a certain texture or smell, or those who resist any changes to their food may also exhibit mild signs of autism.

Remember that this is a very rare problem that parents face, so don’t worry if you notice any of these symptoms.

Pay special attention to your child’s sensory reactions. For example, if they are very sensitive to light or sound, it’s something you should monitor.

A constant oral movement like chewing or sucking can also be a sign of an issue.

Moebius Syndrome

One other possible cause for a constant open mouth posture in babies is a very rare condition called Moebius syndrome.

This rare neurological disorder is present at birth and affects the cranial nerves.

A very common sign that a baby has Moebius syndrome is if they’re drooling a lot and show signs of having crossed eyes.

Since the eyes don’t move laterally if they have this syndrome, your baby may have to turn their head to follow objects with their eyes.

Many infants that have Moebius syndrome may lack facial expression, particularly when they laugh or cry.

This is because the syndrome affects the muscles in the face, which may also cause a frequently open mouth.

Some babies with Moebius syndrome can have problems eating or swallowing. They may also have a short or malformed tongue and an unusually small jaw.

Problems with speech are also very common.

Aside from the eyes and mouth, babies with Moebius syndrome can also experience skeletal malformations of the limbs. This affects over half of children diagnosed with the syndrome.

Underdevelopment of the fingers or hands, as well as webbed fingers and underdevelopment of the chest on one side, are very common.

Pay very close attention to your baby and how they are developing.

If they’re having trouble accomplishing important milestones like crawling or walking, there could be a health problem that needs to be addressed.

There is a close relation to Moebius syndrome and autism, and some children could be misdiagnosed.

Develop a good relationship with your pediatrician and have your baby examined as much as possible if you’re concerned.

What Can Parents Do?

If you’re concerned about your baby’s open mouth posture, there are some things you can do at home to rectify the problem.

Monitor your little one carefully and report any concerns or unusual changes to your pediatrician right away.

Discourage your child from sucking their thumb, and try to keep pacifier use to a minimum.

As soon as they are old enough, move your child from sippy cups to regular cups to help strengthen the jaw muscles.

Make sure the humidity level in your baby’s room is at a comfortable place and try to elevate their head slightly while they sleep.

Rule out any other possible causes like a head cold, allergies, or asthma.

With a few careful changes, your baby should be able to sleep and play with their mouth closed over time.

If you’re ever unsure about why your baby’s mouth is always open, make an appointment with their doctor as soon as possible.

Older children can practice a few simple jaw exercises that will encourage the mouth to stay closed.

Always rule out any serious problems like autism, tongue-tie, or Moebius syndrome while your child is in the infant stages whenever possible.

Healthy Baby, Happy Family

Playing or sleeping with an open mouth posture is not uncommon.

Just make sure that your newborn is getting the sleep they need and eating the way they should so they can grow up happy and healthy.

If you’re ever unsure about why your baby’s mouth is always open, it’s best to see a doctor who can help determine the underlying cause.

Encourage good oral habits and monitor your baby closely and they should grow out of the open mouth phase in time.

Visit my blog to learn about helpful parenting tips and information for mothers, and to find out more about me today!

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Wednesday 24th of May 2023

This article is poorly written and does not provide accurate information. If you are reading this article and are concerned about your babies open mouth posture please reach out to your child’s doctor and request an assessment from an airway focused ear nose and throat specialist (ENT)


Sunday 13th of March 2022

My baby’s mouth is always slightly open, but she had a significant lip and tongue tie which we recently removed via a laser revision. If her mouth doesn’t begin closing on its own, could it also be an autism issue? She’s hitting all her milestones but as a FTM I’m just worried about all the scenarios.

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