Persistent pulmonary hypertension of the newborn (PPHN) presents with which statement about pulmonary arterial pressure?

• A. No difference between pulmonary and systemic pressures
• B. Pulmonary artery pressure lower than systemic pressure
• C. Pulmonary artery pressure higher than systemic pressure
• D. Systemic hypertension

Answer: (D)

In persistent pulmonary hypertension of the newborn, the critical idea is that the pulmonary circulation remains constricted after birth, so the pulmonary arterial pressure stays high relative to the systemic circulation. Normally, after birth the pulmonary vascular resistance falls and the pulmonary pressure drops below systemic pressure. In PPHN, that fall does not occur, so the pulmonary arterial pressure remains elevated and often exceeds systemic pressure. This high pulmonary pressure drives right-to-left shunting through fetal channels like the foramen ovale and ductus arteriosus, leading to significant hypoxemia despite oxygen therapy. Systemic hypertension isn’t the defining feature here; the hallmark is the elevated pulmonary pressure compared with the systemic circulation.