What Is Respiratory Distress Syndrome?

Respiratory distress syndrome (RDS) is a breathing problem that sometimes affects babies born about 6 weeks or more before their due dates. Their lungs aren't developed enough to make surfactant (sur-FAK-tant). Surfactant is a liquid that coats the inside of the lungs and keeps them open so that the baby can breathe in air once he or she is born.

Without surfactant, the lungs collapse and the baby has to work hard to breathe. The baby might not be able to breathe in enough oxygen to support the body's organs.

Most infants who develop RDS show signs of breathing problems at birth or within the next few hours. If they're not given the right treatment, their brains and other organs may suffer from the lack of oxygen.

Overview

RDS is one of the most common lung disorders in premature babies. It affects about 10 of every 100 premature infants in the United States, or about 40,000 babies, each year. In fact, nearly all babies born before 28 weeks of pregnancy develop RDS. Full-term infants rarely get it.

RDS is different from bronchopulmonary dysplasia (BPD), another breathing condition that affects premature babies. While RDS usually develops in the first 24 hours after birth, BPD usually develops within the next week or two. Doctors aren't sure exactly what causes BPD, but they do know that most babies who develop it are born with serious RDS.

All of these babies lack surfactant. But the babies with RDS who go on to develop BPD have less developed lungs than the babies with RDS who recover. Their lungs usually have fewer, larger alveoli, with fewer tiny blood vessels than normal. The blood vessels are needed to move oxygen from the alveoli into the bloodstream.

Outlook

Thanks to recent medical advances, most babies with RDS who weigh more than 2 pounds at birth now survive and have no long-term health or development problems.

May 2007