The observation that an infant frequently holds their mouth open or breathes through it can be concerning for parents. Newborns are often described as obligate nose-breathers, but this pattern begins to change around three to six months of age as their airway develops. When a baby consistently breathes orally, it warrants attention. While it can be a temporary response to congestion, chronic mouth breathing may indicate an underlying issue with the airway that needs professional assessment.
Common Reasons for Mouth Breathing
The most frequent cause for a baby breathing through their mouth is a simple obstruction in the nasal passages that forces them to seek an alternative route for air. Temporary causes of nasal congestion are common, such as a cold, a minor infection, or seasonal allergies, where mucus and inflammation block the narrow nasal airway. Because nasal passages account for a significant portion of total airway resistance in newborns, even minor congestion can trigger mouth breathing.
Chronic mouth breathing is often linked to structural or anatomical factors that prevent clear nasal airflow, even when the baby is not sick. A frequent culprit is the enlargement of the adenoids or tonsils. These lymph tissues are located near the back of the nasal and oral cavities, and when swollen, they can physically block the upper airway, forcing the jaw to drop to draw air in.
Structural issues within the nose itself can also be responsible. A deviated septum, which is an abnormal positioning of the cartilage and bone dividing the nostrils, can significantly impair airflow. Nasal polyps or enlarged turbinates, structures that warm and moisten inhaled air, can swell due to allergies or chronic irritation, leading to persistent nasal blockage.
In some cases, the open-mouth posture is related less to an obstruction and more to muscular or habitual factors. Low muscle tone (hypotonia) in the facial and jaw muscles can make it difficult for a baby to keep their lips sealed. Furthermore, the open-mouth habit can sometimes persist as a learned pattern, especially during sleep, even after initial congestion clears.
Potential Health and Developmental Effects
Prolonged mouth breathing can lead to consequences for a baby’s developing oral and dental health. When air bypasses the nose, the oral cavity dries out because the moisturizing and filtering functions of the nose are lost. This reduction in salivary flow increases the risk of developing cavities and gum inflammation, such as gingivitis, since saliva normally neutralizes acids and washes away bacteria.
The constant open-mouth posture also influences the physical development of the face and jaw bones. When the mouth is open, the tongue rests low instead of against the palate. This lack of upward pressure means the upper jaw (maxilla) may not develop correctly, potentially leading to a high, narrow palate and overcrowded dental arches.
This altered growth pattern can contribute to “adenoid facies,” characterized by an elongated facial structure and potential misalignments of the teeth (malocclusion). The lower jaw may also shift position to compensate for the airway restriction, further impacting the bite. These developmental changes can lead to difficulty with speech development and proper swallowing patterns.
Chronic mouth breathing is also associated with reduced sleep quality, affecting overall development and behavior. Airway restriction can lead to conditions like obstructive sleep apnea, characterized by loud snoring, snorting, or visible pauses in breathing during sleep. Poor sleep can manifest during the day as irritability, difficulty concentrating, or excessive sleepiness.
When to Consult a Specialist
Parents should seek medical advice if the baby’s mouth breathing is a consistent pattern, rather than an occasional occurrence due to a temporary cold. Specific signs that warrant consultation include noisy breathing, persistent snoring, or visible pauses in breathing while the baby sleeps. Difficulty with feeding, such as choking or struggling to coordinate sucking and breathing, also suggests the nasal airway may be severely compromised.
If the mouth-open posture persists after temporary congestion clears, or if the baby exhibits chronic chapped lips or dry mouth, consult a healthcare professional. The first step is typically a visit to the pediatrician, who can assess for common issues like allergies or enlarged tonsils and adenoids. They may then refer the baby to specialized medical professionals for a detailed evaluation.
Depending on the suspected cause, the baby may be referred to a pediatric otolaryngologist (ENT specialist) for a comprehensive assessment of the upper airway. Structural concerns related to the jaw, palate, or teeth may require consultation with a pediatric dentist or an orthodontist. Early intervention is the most effective approach to prevent long-term developmental changes.