Meconium

Meconium is the earliest stool of a mammalian 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, unlike later feces, is viscous and sticky like tar, its color usually being a very dark olive green; it is almost odorless. When diluted in amniotic fluid, it may appear in various shades of green, brown, or yellow. It should be completely passed by the end of the first few days after birth, with the stools progressing toward yellow (digested milk).Meconium from 13-hour-old newborn.This image compares the appearance of meconium (from 48 hours after normal delivery at term) to the appearance of the same infant's feces after 1 week of breastfeeding. Meconium is the earliest stool of a mammalian 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, unlike later feces, is viscous and sticky like tar, its color usually being a very dark olive green; it is almost odorless. When diluted in amniotic fluid, it may appear in various shades of green, brown, or yellow. It should be completely passed by the end of the first few days after birth, with the stools progressing toward yellow (digested milk). Meconium is normally retained in the infant's bowel until after birth, but sometimes it is expelled into the amniotic fluid (also called 'amniotic liquor') prior to birth or during labor and delivery. The stained amniotic fluid (called 'meconium liquor' or 'meconium stained liquor') is recognized by medical staff as a possible sign of fetal distress. Some post-dates pregnancies (where the woman is more than 40 weeks pregnant) may also have meconium stained liquor without fetal distress. Medical staff may aspirate the meconium from the nose and mouth of a newborn immediately after delivery in the event the baby shows signs of respiratory distress to decrease the risk of meconium aspiration syndrome. The issue of whether meconium is sterile remains debated and is an area of ongoing research. Although some researchers have reported evidence of bacteria in meconium, this has not been consistently confirmed. Other researchers have raised questions about whether these findings may be due to contamination after sample collection and that meconium is, in fact, sterile until after birth. Further researchers have hypothesized that there may be bacteria in the womb, but these are a normal part of pregnancy and could have an important role in shaping the developing immune system and are not harmful to the baby The Latin term meconium derives from the Greek μηκώνιον, mēkōnion, a diminutive of μήκων, mēkōn, i.e. poppy, in reference either to its tar-like appearance that may resemble some raw opium preparations, or to Aristotle's belief that it induces sleep in the fetus. A symptom of both Hirschsprung's disease and cystic fibrosis is the failure to pass meconium. Meconium can be tested for various drugs, to check for in utero exposure. Using meconium, a Canadian research group showed that by measuring a by-product of alcohol (FAEE) they could objectively detect excessive maternal drinking of alcohol during pregnancy. In the USA, the results of meconium testing may be used by child protective services and other law enforcement agencies to determine the eligibility of the parents to keep the newborn.