Meconium is passed into the amniotic fluid in approximately 10% of all births. Although passage of meconium may be associated with intrauterine fetal hypoxia, it also occurs in apparently normal deliveries in the absence of asphyxia. It is more common in postmature babies in whom there is evidence of placental insufficiency. Meconium aspiration is not seen in premature infants of less than 34 weeks’ gestation, as these infants rarely demonstrate meconium-stained amniotic fluid.

It is currently recommended that if meconium is present in the amniotic fluid or on the baby’s skin, and the baby is not vigorous, aspiration of meconium from the pharynx and trachea should be performed immediately after birth. The delivery room management of infants born with meconium is discussed in Chapter 24, The Newborn Intensive Care Unit.