Clinically, the hallmarks of the disorder are abdominal distention and failure to pass significant meconium in the first 24 hours of life. Bilious vomiting may occur.4 Symptoms often are present before the first feeding, which helps distinguish the disorder clinically from necrotizing enterocolitis.
The incidence is increased in premature infants of diabetic mothers (especially the small left colon variant) and in infants whose mothers received magnesium sulfate for treatment of toxemia. Newborns with cystic fibrosis also may present with meconium plug syndrome, although meconium ileus is more frequent and characteristic in these patients. Despite these associations, many patients have no apparent risk factor.