Meconium is a thick, black, tarry substance that is presentin the fetal intestinal tract. It is composed of amniotic fluid, lanugo (the fine hair that covers the fetus), bile, and fetal skin and intestinal cells. The neonate’s first stool con-sists of meconium. However, the fetus may pass the meco-nium in utero, which is a sign of fetal stress. Meconium passage is detected during labor when the amniotic fluid is stained dark green or black.
Meconium aspiration syndrome, a condition caused byinhalation of meconium-stained amniotic fluid by the fetus, occurs in about 6% of births in which meconium is present. Severe cases of this syndrome may cause pneumonitis, pneumothorax, and pulmonary artery hypertension.
When there is thick meconium at delivery, interven-tions to prevent or decrease meconium aspiration syn-drome should be considered. Because meconium passage maypredate labor, amnioinfusion should not be used as a preventive measure for meconium aspiration syndrome. Suctioning of theupper airway should be performed after delivery of the head. If the infant is not vigorous and thick meconium is present, the fetus should be intubated and suctioning to re-move material below the glottis should be performed before initiating positive-pressure ventilation. If the infant is ac-tive, suctioning and intubation are therapeutic options that are part of ongoing stabilization and care.