Meconium is the earliest stools of an infant. Unlike later feces, meconium is 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 almost 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 to Aristotle's belief that it induces sleep in the fetus.
Hirschsprung's disease presents as failure to pass meconium.
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.
Meconium can be tested for various drugs, to check for in utero exposure. In the USA, the results of meconium-testing run on a newborn can be turned in to child protective services and other law enforcement agencies.
Meconium ileus should be distinguished from meconium plug syndrome, in which a tenacious mass of mucus prevents the meconium from passing.
Meconium Nicotine and Metabolites by Liquid Chromatography-Tandem Mass Spectrometry: Differentiation of Passive and Nonexposure and Correlation with Neonatal Outcome Measures
Dec 01, 2008; BACKGROUND: Meconium analysis is a diagnostically sensitive and objective alternative to maternal self-report for...