What is a common cause of respiratory distress in newborns?

A common cause of respiratory distress in newborns is mucous obstruction of the nose. In the neonatal period, infants are obligate nasal breathers, meaning that they primarily breathe through their noses. When there is an obstruction from mucous, it can significantly impede their ability to inhale adequate amounts of air, leading to respiratory distress. This condition is often characterized by the newborn's struggle to breathe, which can result in cyanosis and increased respiratory effort.

In contrast, while unrecognized metabolic alkalosis, persistent pulmonary hypotension, and maternal use of a narcotic analgesic can contribute to complications in newborns, they are less direct causes of respiratory distress. Metabolic alkalosis typically manifests in ways that are less directly tied to immediate respiratory function, while persistent pulmonary hypotension relates more to vascular resistance issues in the lungs. Maternal narcotic use can lead to withdrawal symptoms in the newborn but does not directly cause mucous obstruction, which is a more straightforward and immediate issue for newborn respiration.