How long after birth does PPHN typically present?

• A. Within minutes
• B. 24 hours
• C. 3-5 hours
• D. A week later

Answer: (B)

Persistent pulmonary hypertension of the newborn (PPHN) typically presents within the first few hours after birth, often around 24 hours. This condition occurs when the newborn's circulatory system does not transition properly from fetal to neonatal life, leading to high blood pressure in the pulmonary arteries.

At birth, the significant changes in physiology require a rapid decrease in pulmonary vascular resistance, facilitated by various factors including oxygenation and ventilation. In PPHN, however, this transition is impaired, leading to sustained high blood pressure in the lungs and reduced blood flow to the lungs, which can result in severe respiratory distress.

The timing of the presentation is crucial for recognition and management, as early intervention is key. This is different from other potential conditions that might arise in the perinatal period, which can manifest either immediately (within minutes) or later than 24 hours postpartum.