Bronchopulmonary Dysplasia (BPD)

Why BPD develops

Babies' lungs develop most of their air sacs (alveoli) in the last weeks of pregnancy and early childhood. A baby born at 24 to 28 weeks has lungs that are still forming. The life-saving treatments they need, such as oxygen and mechanical ventilation, together with infection and inflammation, interrupt this development.

The "new BPD" seen today mostly reflects arrested development: fewer and larger air sacs and abnormal blood vessels, rather than the heavy scarring seen decades ago.

Risk factors

• birth before 28 to 30 weeks, and very low birth weight
• respiratory distress syndrome needing ventilation
• high levels of oxygen for long periods
• infections before or after birth, including chorioamnionitis and sepsis
• a patent ductus arteriosus (an open heart vessel)
• poor growth in the womb
• male sex and family history of asthma
• maternal smoking

Grading of BPD

Definitions vary somewhat between neonatal networks, but all use support at 36 weeks.

Symptoms

• fast or labored breathing
• needing extra oxygen to keep oxygen levels normal
• retractions (skin pulling in between the ribs)
• wheezing and cough
• tiring easily with feeds and slow weight gain
• frequent drops in oxygen with crying, feeding or illness

Complications

• Pulmonary hypertension: high blood pressure in the lung arteries, straining the heart. Screened with echocardiograms.
• Severe chest infections, especially RSV and bronchiolitis, often needing hospital admission.
• Poor growth, because breathing uses extra calories.
• Airway narrowing (tracheomalacia or subglottic stenosis) after long ventilation.
• Reflux and feeding difficulties.
• Developmental delays, linked partly to prematurity overall.
• Asthma-like symptoms and reduced lung function later in childhood and adulthood.

Diagnosis

BPD is diagnosed in the neonatal intensive care unit based on the baby's gestational age and oxygen or support needs at 36 weeks. Tests support care:

• oxygen saturation monitoring and blood gases
• chest X-rays
• echocardiograms to look for pulmonary hypertension
• sometimes CT scans or airway endoscopy in severe cases

Treatment

In the NICU

• Gentle breathing support: CPAP or high-flow oxygen rather than ventilators where possible, to protect the lungs.
• Caffeine for apnea of prematurity, which also reduces BPD.
• Targeted oxygen levels, avoiding both too little and too much.
• Nutrition: high-calorie breast milk fortifiers or special formulas to support lung growth.
• Diuretics to reduce fluid in the lungs in some babies.
• Steroids (such as low-dose dexamethasone or hydrocortisone) for babies who cannot come off a ventilator, balancing benefits against developmental risks.
• Inhaled medicines in selected babies.
• Pulmonary vasodilators for pulmonary hypertension.

At home

Many babies go home on low-flow oxygen through a nasal cannula, with a pulse oximeter. Parents learn to:

• adjust and check oxygen equipment
• recognize signs of breathing difficulty
• keep the home smoke-free and away from fireplaces and open flames, because oxygen fuels fires
• feed with fortified milk and monitor weight

Oxygen is weaned gradually by the pediatric lung specialist as the baby grows, often within the first year.

Preventing infections

• RSV prevention: a long-acting RSV antibody given to infants, or maternal RSV vaccination during pregnancy, reduces severe RSV. Babies with BPD may qualify for additional doses in their second season.
• Routine vaccines on schedule by age from birth, plus yearly flu vaccine from 6 months and vaccines for family members.
• Handwashing, avoiding sick contacts and crowded places in winter, and no smoking or vaping near the baby.

Outlook

Lung tissue keeps growing through childhood, so most children with BPD improve steadily. Most mild and moderate cases come off oxygen by the first or second birthday. Children may have more wheezing, asthma-like symptoms and reduced exercise tolerance, and some have lower lung function as adults, making it important to avoid smoking. Severe BPD with pulmonary hypertension carries more risk and needs specialist follow-up.

Frequently asked questions

What causes bronchopulmonary dysplasia?

BPD results from very premature birth combined with treatments the baby needed, such as oxygen and ventilation, plus infection and inflammation. These interrupt normal development of the air sacs and blood vessels in the lungs. It mainly affects babies born before 30 weeks.

Is bronchopulmonary dysplasia permanent?

The lungs continue growing and healing through childhood, so most children improve considerably. Many come off oxygen within 1 to 2 years. Some have long-term effects such as asthma-like symptoms and lower lung function, which are usually mild.

How long do babies with BPD need oxygen?

It varies with severity. Many babies with mild or moderate BPD need home oxygen for several months and are weaned within the first year. Babies with severe BPD may need oxygen or breathing support for longer. Weaning is guided by oxygen saturation monitoring.

Can BPD be prevented?

Preventing premature birth is the most effective step. In the NICU, steroids given to the mother before preterm birth, surfactant, gentle breathing support, caffeine and good nutrition reduce the risk. Not all cases can be prevented.

Is RSV dangerous for babies with BPD?

Yes. Babies with BPD are at high risk of severe RSV infection and hospital admission. Long-acting RSV antibody injections or maternal RSV vaccination, handwashing and avoiding sick contacts during RSV season are important protections.