This type of aspiration can result in Meconium Aspiration Syndrome (MAS) when it transpires in mild to severe respiratory difficulties in the newborn, which, in the rare worst-case scenario, may result in infant fatalities.

Meconium is found in the amniotic fluid (the liquid that surrounds a fetus during pregnancy) in 8-25% of all births that occur after the 34th week of gestation. It is very rarely found in this fluid of babies born prematurely, as fetuses do not typically develop the internal organs and functions capable of creating and expelling meconium before the 34th week in the womb.

The presence of meconium does not necessarily mean that a baby will have or develop MAS (the clinical diagnosis of respiratory and other complications that occur after a fetus or baby has inhaled meconium). This Syndrome occurs in about 5% (some statistics cite a higher figure of up to 10%) of babies born with meconium present in the amniotic fluid. Due to more understanding of the effects and causes of MAS, healthcare providers are better able to prepare for and react quickly to the presence of meconium upon birth, thereby preventing the development in babies who are born with meconium present in such fluid. As such, some studies have noted that the incidence of the Syndrome even where meconium release is detected upon birth is decreasing in these industrial countries. In contrast, in developing countries where prenatal care is less available, and a higher percentage of babies are born at home, experts postulate that the incidence of the Syndrome is higher, and the effects are more likely to cause infant fatalities.