Which of the following is the most common congenital respiratory disorder?

Pulmonary hypoplasia is the most common congenital respiratory disorder because it refers to an underdevelopment of the lungs, which can significantly impact respiratory function from birth. This condition often results from factors such as diaphragmatic hernia, oligohydramnios, or congenital malformations that inhibit lung growth. Pulmonary hypoplasia is a critical condition that can lead to serious complications, including respiratory failure and the need for immediate intervention after birth.

While asthma, pneumonia, and cystic fibrosis are significant respiratory issues, they are not classified as congenital disorders. Asthma is typically an acquired condition influenced by environmental and genetic factors, and it can develop at any age. Pneumonia is an infection that affects the lungs and can occur due to various causes, including bacteria, viruses, and fungi. Cystic fibrosis, although genetic, is characterized primarily by malfunctioning exocrine glands affecting the lungs and digestive system, but it does not have the same prevalence as pulmonary hypoplasia as a congenital condition. Thus, pulmonary hypoplasia stands out as the most common congenital respiratory disorder.