What event does atelectasis typically describe in newborns?

Atelectasis refers to the partial or complete collapse of the lung or lung segments, which is commonly seen in newborns who have not yet fully expanded their lungs after birth. This condition can be a result of various factors, including insufficient surfactant production or a retained meconium blockage that prevents lung expansion. When a newborn does not manage to establish adequate lung expansion immediately after birth, it can lead to atelectasis, impacting their ability to breathe efficiently and receive sufficient oxygen. Therefore, the correct understanding of atelectasis in this context is that it describes the condition of unexpanded lungs at birth, which is critical to recognize in managing neonatal respiratory health.