What are thick tarry feces called that a fetal colon accumulates?

Thick, tarry feces that accumulate in a fetal colon are called meconium. Meconium is the first stool of a newborn, composed of amniotic fluid, bile, and cells shed from the intestinal lining. It is typically dark green or black in color and is usually expelled within the first few days after birth. In some cases, if meconium is passed before or during labor, it can pose risks to the baby, such as meconium aspiration syndrome.