Meconium

The thick, sticky, greenishblack faeces passed by infants in the first day or two after birth. It consists of bile, mucus, and shed intestinal cells. Occasionally, the fetus passes meconium into the amniotic fluid in the uterus. This is more common in babies who experience fetal distress during labour or who are over 40 weeks’ gestation. Meconium in the amniotic fluid may be inhaled when the baby starts to breathe, sometimes blocking the airways and damaging the lungs. In some babies with cystic fibrosis, the meconium is so thick and sticky that it blocks the intestine (see intestine, obstruction of).