Pulmonary hypoplasia may be caused by which condition?

• A. Intrauterine growth retardation (IUGR)
• B. Pulmonary interstitial emphysema
• C. Neonatal jaundice
• D. Congenital diaphragmatic hernia (CDH)

Answer: (D)

Pulmonary hypoplasia happens when the lungs don’t develop to normal size and structure because fetal growth in the chest is restricted. The most classic cause is a congenital diaphragmatic hernia, in which abdominal organs move into the thoracic cavity. That herniation crowds the developing lungs, limiting airway branching and lung tissue growth, leading to smaller, underdeveloped lungs at birth. This situation also sets up risks like severe respiratory distress and pulmonary hypertension after birth due to the abnormal pulmonary vasculature.

Other conditions don’t typically produce this mechanical crowding of the chest. Intrauterine growth restriction can lead to overall smaller organs, but it’s not the classic direct cause of pulmonary hypoplasia like CDH. Neonatal jaundice involves liver processing of bilirubin, not lung development. Pulmonary interstitial emphysema is air leakage related to ventilation in the newborn, not a primary developmental hypoplasia.