A newborn delivered at 28 weeks' gestation presents with severe respiratory distress. Which of the following best explains this finding?

In the context of a prematurely born infant, particularly one delivered at 28 weeks of gestation, severe respiratory distress can largely be attributed to underdeveloped lungs, which have not yet matured sufficiently to function effectively in gas exchange. One of the critical physiological aspects that contribute to the respiratory difficulties seen in these newborns is lung elastic recoil.

Lung elastic recoil refers to the lungs' ability to return to their original size after being stretched during inhalation. In premature infants, the lungs may lack adequate surfactant, which is crucial for reducing surface tension within the alveoli, thus promoting elastic recoil and preventing the collapse of alveoli upon exhalation. The absence of reflexive recoil leads to atelectasis (collapse of the alveoli), which subsequently causes respiratory distress due to impaired oxygenation and ventilation.

Therefore, the best explanation for the severe respiratory distress in a 28-week gestation newborn is the compromised lung elastic recoil, which hinders the infant's ability to effectively inhale and exhale air, contributing significantly to respiratory distress following birth.