Pneumothorax in Newborn: Causes, Symptoms, and Treatment

Pneumothorax, the presence of trapped air between the lung and chest wall, affects roughly 5 out of every 1,000 neonatal hospital discharges in the United States and is the most common type of air leak in newborns. It can occur spontaneously in otherwise healthy full-term babies during their first breaths, or it can develop as a complication of respiratory support, lung disease, or difficult deliveries. The condition ranges from a small, self-resolving air collection to a life-threatening tension pneumothorax that demands emergency intervention within minutes.

How Common It Is and Who Is Most at Risk

Large studies put the overall incidence of neonatal pneumothorax at about 4 to 6 per 1,000 live births, though the rate varies depending on the population studied. A Swiss regional network covering more than 32,000 births over two and a half years found an incidence of about 0.56 per 100 live births, with roughly three-quarters of affected infants being male and about 81 percent born at term.¹ A cohort study across three neonatal intensive care units found an overall prevalence of 0.53 percent among all admissions, but the rate climbed sharply with decreasing gestational age: about 0.39 percent in near-term and term infants, 4 percent in babies born at 29 to 34 weeks, and roughly 4.6 percent in those born at 28 weeks or earlier.² In a U.S. dataset of 7.7 million neonatal discharges, pneumothorax accounted for about 4.3 per 1,000 discharges, with an overall air-leak mortality rate of 7.2 percent.³

The male predominance shows up consistently across studies, with boys accounting for roughly two-thirds to three-quarters of cases. Beyond sex and prematurity, the major risk factors fall into two broad categories: conditions that create uneven lung inflation and medical interventions that push air under pressure into fragile lung tissue.

What Causes Neonatal Pneumothorax

In full-term newborns, the most common scenario is a so-called spontaneous pneumothorax. During the first breaths after birth, a baby generates very high pressures to inflate lungs that have never held air. If that pressure distributes unevenly, a small air sac can rupture and leak air into the space around the lung. Many of these cases are mild. For near-term and term babies, most pneumothoraces show up within the first 24 hours of life.²

In preterm infants, the lungs are structurally immature, with less surfactant to keep air sacs open and thinner tissue that tears more easily. These babies are far more likely to need breathing support, and that support itself is one of the leading causes of pneumothorax. Mechanical ventilation, particularly when it uses high peak inspiratory pressures, is strongly associated with the development of air leaks. Studies have shown that infants who developed pneumothorax while on ventilators had been exposed to significantly higher peak inspiratory pressures and higher oxygen concentrations than those who did not.² Minimizing peak pressure and carefully managing end-expiratory pressure are considered key strategies for reducing this risk.⁴ That said, the relationship is not perfectly straightforward in every subgroup. One study of extremely low birth weight neonates found no statistically significant difference in ventilatory pressures between those who developed pneumothorax and those who did not, suggesting that in the tiniest babies, other factors like lung immaturity itself may matter more than pressure settings alone.⁵

Even non-invasive respiratory support carries some risk. Delivery-room continuous positive airway pressure (CPAP), widely used to help near-term and term babies breathe, was independently associated with a more than doubled risk of pneumothorax in one large cohort.² This does not mean CPAP is inherently dangerous; the benefit of helping a struggling baby breathe usually outweighs the air-leak risk. But it is a reminder that any positive-pressure breathing support in a newborn carries some chance of over-distending fragile lung tissue.

Specific lung diseases also set the stage. Meconium aspiration syndrome, where the baby inhales stool-contaminated amniotic fluid during or before delivery, accounts for a meaningful share of cases. The thick, sticky meconium can partially block airways, trapping air behind it and causing rupture when the baby tries to breathe out. Meconium aspiration has been reported as a cause in roughly one in five neonatal pneumothorax cases.⁶ Congenital diaphragmatic hernia, persistent pulmonary hypertension, and respiratory distress syndrome are other conditions that increase the likelihood of air leaks.³

Recognizing the Symptoms

The signs of neonatal pneumothorax vary depending on the size of the air leak and whether the baby was already receiving respiratory support. In otherwise healthy term babies, the most common presenting symptom is tachypnea, or abnormally fast breathing. A study focused on symptom presentation found that all affected neonates showed respiratory symptoms within the first 48 hours of life, with rapid breathing being the dominant finding.⁷

The timing and severity of symptoms differ between larger and smaller babies. Infants weighing at least 2,500 grams at birth were typically diagnosed at a median age of about 5.5 hours, and most of them (around 70 percent) did not need intubation. Smaller infants, those under 2,500 grams, tended to present later, at a median of 34 hours, and their pneumothorax often announced itself through rising carbon dioxide levels and an increasing need for supplemental oxygen. Nearly 90 percent of these smaller babies required mechanical ventilation after the pneumothorax developed.⁸ This pattern makes sense: larger babies are more likely to have a spontaneous pneumothorax that shows up quickly, while smaller, sicker babies often develop pneumothorax as a complication of existing lung disease and ventilation, meaning the air leak builds over time.

Beyond tachypnea, other warning signs include grunting, cyanosis (a bluish discoloration of the skin), chest asymmetry with one side appearing more distended, and a sudden deterioration in a baby who was previously stable on respiratory support. In the worst-case scenario, a tension pneumothorax, the trapped air progressively compresses the lung and shifts the heart and major blood vessels, leading to a rapid drop in heart rate and blood pressure. This is a genuine emergency.⁹

How Neonatal Pneumothorax Is Diagnosed

Speed matters, especially when a baby is deteriorating rapidly. The oldest and fastest bedside method is transillumination: a bright fiber-optic light is pressed against the infant’s chest in a darkened room. If a large pocket of air is present, that side of the chest will glow more brightly than the other. This technique has been used for decades as a way to localize severe pneumothorax for immediate treatment without waiting for imaging.¹⁰ Transillumination is imperfect and works best for large air collections, but its value lies in buying time during an emergency.

Chest X-ray has traditionally been the standard confirmatory test. It can show the air collection, lung collapse, and any shift of the heart away from the affected side. However, a systematic review and meta-analysis found that lung ultrasound is actually more accurate than chest X-ray for diagnosing neonatal pneumothorax, with a sensitivity of about 99 percent and specificity of about 98 percent, compared to roughly 82 percent sensitivity for X-ray.¹¹ Ultrasound can be performed right at the bedside without moving the baby, and it does not expose the infant to radiation. Specific ultrasound signs, like the absence of the normal sliding movement of the lung surface, loss of certain artifact patterns, and the identification of a “lung point” where normal and collapsed lung tissue meet, can confirm the diagnosis within seconds.¹²

Radiographic measurements can also help predict whether a pneumothorax will need active intervention. One study developed a size ratio using standard chest X-ray measurements and found that a specific threshold had about 86 percent sensitivity and 88 percent specificity for predicting which infants would need drainage, correctly classifying 87 percent of cases.¹³ Tools like this are useful for the grey-zone cases where the clinical team is weighing whether to watch and wait or to proceed with drainage.

Conservative Management

Not every neonatal pneumothorax needs a procedure. Small pneumothoraces in term babies who are breathing comfortably on their own can sometimes be managed with close monitoring alone. The leaked air gradually reabsorbs into the surrounding tissue over hours to days.

When a baby is mildly symptomatic but stable, one traditional approach is nitrogen washout therapy, which involves giving the infant a high concentration of supplemental oxygen. The rationale is that flooding the blood with oxygen replaces nitrogen in the surrounding tissues, creating a gradient that draws nitrogen out of the trapped air pocket and speeds its absorption. A recent study found that nitrogen washout reduced the median time to resolution compared to targeted oxygen therapy: about 31 hours versus 81 hours.¹⁴ However, this technique is generally reserved for term or near-term infants because of concerns about oxygen toxicity in premature babies, whose retinas and lungs are vulnerable to high oxygen levels.

When Drainage Is Needed

Tension pneumothorax is a medical emergency that demands immediate intervention. The initial step is needle aspiration, where a large-bore needle or small catheter is inserted through the chest wall to release the trapped air and relieve pressure. If that is not enough, tube drainage follows.¹⁵ A Cochrane review comparing needle aspiration with chest-tube drainage in newborns found insufficient evidence to declare one method superior overall, though needle aspiration did reduce the need for subsequent tube placement in some infants.¹⁶

When ongoing drainage is required, the choice is typically between a traditional chest tube and a smaller, more flexible pigtail catheter. Pigtail catheters have gained ground in neonatal care. One study found that pigtail catheters had a significantly higher rate of complete radiological resolution compared to traditional straight drains (96 percent versus about 74 percent), with complications like subcutaneous emphysema and drain malfunction occurring only in the traditional drain group.¹⁷ Pigtail catheters are also faster to insert. One trial found the procedure took about 15 minutes with a pigtail catheter versus about 25 minutes with a conventional chest tube.¹⁸ Additionally, babies with pigtail catheters appear to need less pain medication while the drain is in place.¹⁹

The pigtail catheter’s smaller size does come with a trade-off: a trend toward higher rates of tube dislodgement and kinking. In one study, about 25 percent of pigtail insertions experienced dislodgement or malfunction compared to about 15 percent with traditional tubes, though the difference was not statistically significant.¹⁸ Neither approach showed a clear mortality advantage over the other.

Complications of Neonatal Pneumothorax

Beyond the immediate danger of respiratory failure, pneumothorax in preterm infants carries a specific neurological risk. The rapid hemodynamic changes that occur when air compresses the chest contents can cause a sudden surge in blood flow to the brain. In premature babies, whose blood vessels in and around the brain are exceptionally fragile, this surge can trigger intraventricular hemorrhage, or bleeding into the brain’s ventricles. A study using ultrasound monitoring documented marked increases in cerebral blood flow velocity at the time of pneumothorax, and intraventricular hemorrhage was observed shortly afterward in the affected infants.²⁰ This connection is one reason why preventing pneumothorax in premature babies is treated with such urgency — the stakes go well beyond the lungs.

Overall mortality from neonatal air leak syndromes sits at about 7.2 percent across all gestational ages in the United States.³ But outcomes depend heavily on context. A study from a single maternity hospital found that about 84 percent of neonates with pneumothorax had a good outcome and were discharged, though the majority of cases in that cohort were in premature infants who required significant respiratory support.

Ventilation Strategies That Reduce the Risk

Because mechanical ventilation is one of the major modifiable risk factors, a great deal of research has focused on how to ventilate tiny lungs more safely. The most well-supported strategy is volume-targeted ventilation, where the ventilator delivers a set volume of air with each breath rather than pushing to a set pressure limit. A Cochrane systematic review found that volume-targeted ventilation roughly halved the rate of pneumothorax compared to pressure-limited ventilation.²¹ An earlier meta-analysis found a similar reduction, with volume-targeted modes cutting the risk of pneumothorax by more than half.²²

The logic behind volume targeting is straightforward. A premature infant’s lung compliance can change rapidly, sometimes within minutes, as surfactant is given or as the disease evolves. In pressure-limited modes, the ventilator keeps pushing to the same pressure regardless of how stiff or compliant the lungs have become. If the lungs suddenly become more compliant, that fixed pressure delivers a larger-than-intended breath, over-distending the tissue. Volume targeting avoids this by automatically adjusting the pressure to deliver a consistent, safer breath volume. The benefits are not limited to fewer air leaks: volume-targeted ventilation also reduces the combined risk of death or chronic lung disease, lowers rates of severe brain hemorrhage, and shortens the total time babies spend on the ventilator.²¹

Genetic Conditions Linked to Pneumothorax

While most neonatal pneumothorax is caused by the factors discussed above, a small number of cases occur in the context of inherited conditions that weaken lung tissue or alter its structure. Connective tissue disorders like Marfan syndrome, vascular Ehlers-Danlos syndrome, and Loeys-Dietz syndrome can make the lung’s structural scaffolding more fragile and prone to rupture. Cystic fibrosis and alpha-1 antitrypsin deficiency affect the airways and lung parenchyma in ways that increase air-leak risk over a lifetime, though they rarely present with pneumothorax in the newborn period. Rarer syndromes like Birt-Hogg-Dubé syndrome and tuberous sclerosis-associated lymphangioleiomyomatosis are also recognized causes of spontaneous pneumothorax, primarily in older patients.²³

For most families, a single episode of neonatal pneumothorax does not signal an underlying genetic condition. But if pneumothorax recurs, if the baby has other features suggestive of a connective tissue disorder (unusually flexible joints, tall and slender body type, a family history of spontaneous pneumothorax), or if the air leak seems disproportionate to the clinical situation, further genetic evaluation may be warranted. These scenarios are uncommon, but recognizing them early can change long-term management and surveillance.

Why Left-Side Versus Right-Side Matters

Neonatal pneumothorax does not always behave the same on both sides of the chest. In clinical practice, right-sided pneumothoraces tend to be slightly more common, which some researchers attribute to subtle anatomical differences in how the right and left bronchial trees branch. A left-sided tension pneumothorax can be more immediately dangerous because the heart sits toward the left, meaning even a moderate amount of trapped air can compress it and compromise circulation faster than the same amount of air on the right side. In rare cases, bilateral pneumothorax occurs in both lungs simultaneously, which is especially perilous in a premature infant already on respiratory support.¹⁵

For parents, the laterality of the pneumothorax is something the medical team takes into account but is not typically something to worry about independently. Whether the air leak is on the left, the right, or both sides, the diagnostic and treatment approach follows the same general principles: identify the air, assess how much trouble it is causing, and decide whether to watch closely or intervene with drainage. The key prognostic factors remain gestational age, the underlying lung condition, and how quickly the pneumothorax is recognized and managed.

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