Respiratory distress syndrome (RDS) of infants, sometimes called hyaline membrane disease, is a serious condition that most commonly occurs in babies who are born before their lungs are fully developed. The lungs do not fully inflate or function normally, making breathing difficult or impossible without medical intervention.

RDS occurs when the lungs fail to produce enough surfactant, a substance that helps the lungs stay properly inflated. Normally, the lungs produce surfactant close to the time of birth. Babies born before the lungs have produced this substance often require oxygen therapy or a ventilator machine to help them breathe. A baby's lungs usually will improve after a medicine form of surfactant is delivered through a breathing tube into the lungs.