Meconium aspiration syndrome occurs when an infant inhales meconium during delivery or the first breath. Meconium passes into the amniotic fluid when the fetus experiences distress or lack of oxygen in the womb. After birth, the thick meconium can be aspirated into the lungs, causing airway obstruction and respiratory distress like fast breathing, grunting, and cyanosis within a few hours. The aspiration leads to overexpansion and rupture of alveoli as well as collapsed lung areas.