Meconium

Overview


Meconium is the first stool of an infant, composed of materials ingested during the time the infant spends in the uterus: Intestinal epithelial cells, lanugo, mucus, amniotic fluid, bile, and water. Meconium is sterile, unlike later feces, is viscous and sticky like tar, and has no odor. It should be completely passed by the end of the first few days of postpartum life, with the stools progressing toward yellow (digested milk). The term Meconium derives from meconium-arion, meaning "opium-like", in reference either to its tarry appearance or Aristotle's belief that it induced sleep in the fetus.

Meconium is normally stored in the infant's intestines until after birth, but sometimes it is expelled into the amniotic fluid prior to birth or during labor and delivery. Sometimes the meconium becomes thickened and congested in the ileum, a condition known as meconium ileus. Meconium ileus is often the first symptom of cystic fibrosis.

Meconium can be tested for various drugs, to check for in utero exposure. The results of meconium testing run on a newborn can be turned in to child protective services and other law enforcement agencies.

Meconium is also used to describe the metabolic waste product from the pupal stage that is expelled through the anal opening of the adult butterfly upon eclosion from the chrysalis.