Delay in pulmonary pressure drop after birth can lead to which outcome?

• A. Immediate stabilization
• B. Hypoxia
• C. Decreased respiratory effort
• D. Normal transition

Answer: (B)

The main idea here is that the newborn’s circulation depends on a rapid fall in pulmonary vascular resistance once the lungs expand. When that drop is delayed, the lungs don’t receive as much blood flow as needed, and the right heart remains at higher pressure. This keeps fetal pathways like the foramen ovale and ductus arteriosus open longer, so more blood shunts from right to left and bypasses the lungs. The result is less oxygenated blood reaching the rest of the body, leading to hypoxia. Immediate stabilization and a smooth transition rely on quick lung aeration and the closing of those fetal shunts, so a delayed pressure drop disrupts that process. Decreased respiratory effort isn’t the direct outcome of the delay, though hypoxia can worsen breathing.