A serious condition in which a newborn breathes a mixture of meconium (the first intestinal discharge) and amniotic fluid into the lungs around the time of delivery. meconium aspiration syndrome occurs in 5-10 percent of births and typically occurs when the infant is stressed, as when the infant is past its due date.

Meconium aspiration syndrome (MAS), also known as neonatal aspiration of meconium, is a medical condition affecting newborn infants. It describes the spectrum of disorders and pathophysiology of newborns born in meconium-stained amniotic fluid (MSAF) and have meconium within their lungs...