What to Know About Mouth Breathing In Babies and Children

Medically Reviewed by Renee A. Alli, MD on September 04, 2023
4 min read

The usual way for your newborn baby to breathe is through their nose. This is unless their nasal passage has some blockage, which can lead to mouth breathing.

Young babies don't develop the reflex to breathe through their mouths until they are 3 or 4 months old. Studies show that mouth breathing while the baby sleeps may be due to some blockage in the upper airway, including the throat and nose. The blockage could be due to a stuffy nose or a more complex condition. 

Mouth breathing can result in long-term health consequences, if left untreated. In many cases, it’s a symptom that indicates airway restriction. Your baby will resort to mouth breathing as an adaptation to help them get enough oxygen.

You’re more likely to notice mouth breathing in your baby or child while they sleep. In other cases, it could be a regular habit even when they’re awake. Regardless of when it happens, mouth breathing is a risk for young and developing brains.

The primary reason why mouth breathing happens has to do with the jaw. Ideally, your child’s jaw should be U-shaped and wide. However, it’s now a common occurrence for jaws to be smaller, leading to overcrowding of the teeth and crooked smiles. They also lead to slack-mouth overbites, and bites that seem to be out of position. The result is V-shaped jaws that cause a high and narrow palate and lead to obstructed nasal passages.

Mouth breathing may also be caused by:

  • Sleep apnea. If your child snores while sleeping, it's not because snoring is normal. Sleep apnea means that their upper airway is blocked in some way. This could be because of adenoids or enlarged tonsils. Other symptoms that accompany snoring include: coughing, pauses in breathing, choking, and restlessness.
  • Allergies. Undiagnosed allergies can create breathing difficulties for your child, causing them to breathe through the mouth.
  • Mucus. When your child’s nose is stuffy or blocked with mucus, they may breathe through their mouth out of necessity.
  • Anatomical problems. One of the most common anatomical problems that lead to mouth breathing is a significantly deviated septum, typically caused by birth trauma. This means that the cartilage and bone separating your baby's nostrils from one another are in abnormal positions. The result is breathing difficulties that cause your child to breathe through their mouth instead.

Your baby is at risk of mouth breathing if:

  • They stop breastfeeding before they are three months old. Even breastfeeding once a day can help your baby reduce the risk of regularly breathing through their mouth. Breastfeeding promotes nose breathing and makes the child’s mouth and tongue muscles engage. The pressure on the child’s palate also enhances bone growth of the jaw, causing it to widen. This leads to a more open airway.
  • They have a tongue-tie. If your child’s tongue frenulum is tight, they’ll have trouble latching and breastfeeding properly. In the long-term, this can also lead to problems with eating, swallowing, and speech in some cases. A tongue-tie also prevents orofacial development, which can potentially lead to partial airway blockage at night.
  • Thumb-sucking and prolonged use of pacifiers. The pressure your babycauses on the palate when sucking their thumb or pacifiers forces the jaw to stay narrow.
  • Enlarged tonsils. Inflamed and swollen tonsils can partly block the airways. This will cause your child to breathe through the mouth when sleeping.


When your child is repeatedly breathing through the mouth while they sleep, it is a sign that they have this condition. Additional signs include:

Everyone should breathe through their nose for good health. As air passes through the nasal path, it is filtered to remove toxins. It also reaches the lungs at optimal pressure, a factor that helps in oxygen extraction and nitric acid release for proper circulation.

When your child breathes through their mouth, fewer toxins are filtered, which can inhibit circulation. This affects the transfer of oxygen throughout the body, impacting your child's wellbeing by causing:

  • Oral health problems such as dry mouth, which reduces saliva and causes bacteria to stay longer on the teeth. This increases the risk of gingivitis and tooth decay.
  • General health problems like high blood pressure, sleep disorders, and allergies
  • Orthodontic problems due to poor jaw development, leading to teeth crowding
  • Poor facial development
  • Speech problems because of the forward thrusting of the tongue
  • Sleep disorders like apnea and snoring.

If you notice mouth breathing symptoms in your child, make an appointment with their pediatric dentist. You will get a referral to another professional for proper diagnosis and treatment. The options include:

  • Breathing retraining and proper tongue posture to teach your child to breathe through their nose
  • Management of allergies, thumb sucking, and infections
  • Orthodontic treatment that involves fitting braces to guide jaw and teeth movement
  • Surgery to remove the physical obstruction like adenoids, deviated septum, tongue-tie, or enlarged tonsils