In pregnancies with premature rupture of membranes, the severity of pulmonary hypoplasia correlates with the duration of which condition?

• A. Hyperglycemia
• B. Polyhydramnios
• C. Intrauterine infection
• D. Maternal fever

Answer: (B)

Pulmonary development relies on a steady amniotic fluid environment to provide stretch and buoyancy for the developing lungs. In pregnancies with premature rupture of membranes, leaking fluid leads to oligohydramnios, and the longer this low-fluid state persists, the more the lungs’ growth and alveolar formation are impaired. The mechanical and fluid-filled conditions that promote normal lung development are lost when amniotic fluid is reduced, so the severity of pulmonary hypoplasia tracks with how long this oligohydramnios lasts. While other maternal or fetal factors can influence pregnancy outcomes, they do not drive the extent of lung underdevelopment as directly as the duration of reduced amniotic fluid. In short, the key determinant is how long the fetus is exposed to low amniotic fluid, with longer exposure associated with more severe pulmonary hypoplasia.