What Causes Bronchopulmonary Dysplasia?

The lungs of babies born more than 10 weeks before they are due are fragile and easily irritated or injured by things in the outside environment during the first hours or days after birth.

Doctors now believe that a baby gets bronchopulmonary dysplasia (BPD) as a result of the way his or her lungs respond to some of these things, including:

• High levels of oxygen. Doctors usually give oxygen to newborns with breathing problems. This is to make sure that their brains, hearts, livers, and kidneys receive enough oxygen to do their jobs. But high levels of oxygen can cause inflammation in the lungs. This can result in injury to the breathing passages. High levels of oxygen also can slow the normal development of the lungs in babies born very early.
• Pressure caused by mechanical ventilation. In the past, doctors usually put newborns who couldn't breathe on their own on mechanical ventilators. These machines apply pressure to push air into the babies' lungs. This pressure can irritate the lungs and cause them to become more inflamed. Mechanical ventilation is a factor in most cases of BPD.
• Doctors try to minimize the injury by using ventilation only when absolutely needed. Today, more and more doctors are putting these babies on nasal continuous positive airway pressure (NCPAP) machines, which don't put the same kind of pressure on the babies' lungs.
• Infections. Infections in babies born early can cause inflammation in their underdeveloped lungs. This narrows the breathing passages and makes it harder for the baby to breathe. Lung infections also increase the baby's need for extra oxygen and help with breathing.

Some doctors think that heredity may be a factor in the development of BPD.