Why are infants born via cesarean delivery more prone to atelectasis?

Infants born via cesarean delivery are more prone to atelectasis primarily due to the mechanics of birth. During a vaginal delivery, the compression of the thoracic cavity occurs as the infant passes through the birth canal. This compression helps to expel amniotic fluid from the lungs and facilitates the initial expansion of the alveoli with air. In contrast, during a cesarean delivery, this important physical process does not happen, which can lead to inadequate lung inflation and a higher risk of atelectasis, or the collapse of part or all of a lung.

The other options, while relevant to certain aspects of respiratory health in neonates, do not directly address the specific mechanism as effectively. For instance, lung development can be a factor, but many infants delivered by cesarean have adequately developed lungs. Analgesics may influence respiratory function, but this effect is not as directly related to the risk of atelectasis as the lack of thoracic compression during delivery. Fluid retention is also a concern in some situations, but it is not the primary reason for the higher incidence of atelectasis in infants born by cesarean section. The key factor remains the absence of vaginal birth's mechanical stimulation that promotes proper lung expansion.