Which drug administered to a mother 24 to 48 hours before delivery reduces the incidence and severity of respiratory distress syndrome?

• A. Antibiotics
• B. Steroids
• C. Tocolytics
• D. Magnesium sulfate

Answer: (B)

Antematal corticosteroids accelerate fetal lung maturation, boosting surfactant production and the enzymes that prepare the lungs for gas exchange. When given before preterm birth, they lower the risk and severity of respiratory distress syndrome by helping the newborn achieve better lung compliance and alveolar stability after birth. The beneficial window is generally after at least 24 hours up to about a week, with the best outcomes when delivery occurs within that timeframe. Typical regimens include betamethasone given as two doses 24 hours apart, or dexamethasone given in four doses over 24 hours, though exact dosing can vary by protocol.

This is why steroids are the best choice in a scenario where the mother is likely to deliver preterm within a 24–48 hour window: they directly prepare the lungs for air breathing at birth, reducing RDS incidence and severity and often improving overall neonatal outcomes. By contrast, antibiotics prevent infection, tocolytics aim to slow labor rather than lung maturation, and magnesium sulfate is used mainly for neuroprotection or other maternal indications rather than reducing RDS.