What is Meconium Aspiration Syndrome?

Amniotic fluid aspiration syndrome, also known as meconium aspiration syndrome, is a common respiratory disorder in newborns. It occurs when a fetus or newborn inhales amniotic fluid contaminated with meconium, and is most commonly seen in full-term or post-term infants. Chemical substances and bacteria present in the meconium can trigger inflammatory responses in the airways and lungs, leading to alveolar ventilation impairment and restricted gas exchange. Severe cases may progress to respiratory distress, hypoxemia, or even respiratory failure.

Clinical manifestations include: rapid breathing and cyanosis in the newborn. Airway obstruction may cause wheezing respiration and bluish skin discoloration. Generalized skin discoloration may occur in fetuses exposed to meconium-stained amniotic fluid for more than 4–6 hours, with the skin, nail beds, and umbilical cord potentially turning yellow-green or deep green.

Main causes of amniotic fluid aspiration syndrome include: fetal distress during intrauterine development or delivery, which may lead to aspiration of amniotic fluid when the fetus experiences hypoxia. Post-term infants are at higher risk as their amniotic fluid is more likely to be contaminated with meconium. Fetal immaturity also contributes, as immature fetuses have difficulty expelling meconium, thereby increasing the risk of aspiration.