Meconium is thick, greenish black, and sticky.
During pregnancy the baby floats in amniotic fluid inside the mother's uterus. This fluid protects the baby while he grows and develops. The baby swallows the amniotic fluid which contains all the other constituents mentioned above. All the contents other than the amniotic fluid itself are filtered out by the existing meconium, thus sterilizing the amniotic fluid which the baby then urinates out. This process of circulation of the amniotic fluid occurs about every 3 hours.