What is the primary cause of Respiratory Distress Syndrome (RDS) in newborns?

• A. A deficiency of surfactant
• B. Excess fluid in the lungs
• C. A congenital heart defect
• D. Upper respiratory infection

Answer: (A)

Respiratory Distress Syndrome (RDS), particularly in premature infants, primarily stems from a deficiency of surfactant. Surfactant is a substance produced in the lungs that reduces surface tension within the alveoli (the tiny air sacs where gas exchange occurs). It plays a critical role in preventing the alveoli from collapsing during exhalation and in improving lung compliance.

When newborns, especially those born prematurely, have insufficient levels of surfactant, they encounter significant difficulties in breathing, leading to RDS. The absence of adequate surfactant results in increased work of breathing and can lead to atelectasis (collapse of alveoli), hypoxemia (low oxygen levels in the blood), and respiratory failure if not managed promptly.

Other listed causes for respiratory difficulties such as excess fluid in the lungs, congenital heart defects, or upper respiratory infections are associated with a variety of respiratory issues but do not specifically cause RDS as primarily as surfactant deficiency does. Each of these conditions can contribute to respiratory problems in newborns; however, they are not the hallmark primary cause of RDS.