What causes pulmonary hypoplasia?

Pulmonary hypoplasia, which refers to the underdevelopment of the lungs, is primarily caused by factors that disrupt normal lung growth during fetal development. One significant cause is compression of the developing lungs by herniated abdominal organs, which can occur in conditions such as congenital diaphragmatic hernia. In such cases, abdominal contents move upward into the thoracic cavity, limiting the space available for lung expansion. This mechanical compression leads to reduced lung volume and inhibits normal lung growth, resulting in pulmonary hypoplasia.

While genetic abnormalities, infectious diseases during pregnancy, and exposure to teratogenic drugs can impact fetal development, they are not the most direct or common causes of pulmonary hypoplasia compared to the mechanical effects of herniated organs. This distinction highlights the importance of understanding the mechanical factors that can impede lung development in the fetal environment.