What is the chief predisposing factor for respiratory distress syndrome (RSD) of the newborn?

The chief predisposing factor for respiratory distress syndrome (RDS) of the newborn is premature birth. RDS is primarily due to inadequate production of surfactant, a substance that helps keep the alveoli (the tiny air sacs in the lungs) open and reduces surface tension within them. Surfactant production typically begins around 24 to 28 weeks of gestation, with significant increases occurring between 34 and 36 weeks.

Premature infants, especially those born before 34 weeks of gestation, often have immature lungs that produce insufficient surfactant, leading to difficulties in breathing and oxygenation after birth. As a result, they are at a significantly higher risk for developing RDS compared to full-term infants.

While factors such as low birth weight, maternal smoking, and alcohol use during pregnancy can contribute to other complications in newborns, they are not direct causes of RDS in the same way that premature birth is. Low birth weight can be a consequence of prematurity, and smoking or alcohol consumption could potentially cause other issues or complications, but the core problem leading to RDS remains the immaturity of the lungs due to premature delivery.