In utero passage of meconium occurs in up to 20% of births, usually in term or near-term neonates. There is a correlation between fetal distress or hypoxia and the passage of meconium prior to delivery. Aspiration of meconium-stained amniotic fluid (MSAF) occurs in up to 10% of such infants, either before delivery, during birth, or during resuscitation. Meconium aspiration can lead to proximal and peripheral airway obstruction, chemical pneumonitis, and persistent pulmonary hypertension. The clinical manifestations of meconium aspiration syndrome (MAS) are variable, ranging from mild tachypnea and hypoxia to fulminant respiratory failure.

As such, treatment of MAS can range from supportive care to full cardiopulmonary support. Infants with severe MAS may require conventional or high-frequency ventilation, surfactant therapy, inhaled nitric oxide, or extracorporeal membrane oxygenation. Mortality is typically <10%, but can be much higher in certain settings. In survivors, the most common sequelae are pulmonary, including prolonged oxygen requirement, exercise-induced bronchospasm, reactive airway disease, and chronic lung disease. Neurologic sequelae, including hypoxic ischemic encephalopathy, can occur but are more closely related to the occurrence of intrauterine asphyxia.

To prevent MAS, traditional teaching has encouraged two methods of suctioning for neonates born through MSAF. The first is intrapartum suctioning, which entails suctioning of the neonate’s nasopharynx and oropharynx after the delivery of the head but prior to the delivery of the shoulders. The second is endotracheal intubation immediately following delivery, with application of suction as the tube is removed. Repeat intubation with tracheal suctioning until the secretions clear is often practiced. Early studies demonstrated a decline in the rate of MAS and a decline in the morbidity
and mortality rate associated with MAS, with the implementation of endotracheal intubation and tracheal suctioning alone or in combination with intrapartum suctioning.