A condition that can occur in newborns where a mass of thickened meconium obstructs the large intestines. The condition may occur as a result of other disorders such as cystic fibrosis, colon atresia, narrowed colon, impaired intestinal motility (Hirschsprung disease) or for no apparent reason. Often, bowel function returns to normal once the meconium plug is passed from the body. See also Meconium plug syndrome