| Condition | Comments |
| Hirschsprung disease | Abdominal distension and vomiting are common. On digital examination, typical findings are a tight anal canal with empty rectum, often with an explosive "squirt" of soft stool when the finger is withdrawn. On contrast enema, a transition zone may be seen but often is not visible in newborns. |
| Intestinal obstruction | Consider atresia, webs, or volvulus. Obstruction may be present even in infants who pass meconium. |
| Meconium ileus | Symptoms often begin on second day of life. Most patients with meconium ileus have cystic fibrosis. |
| Meconium plug syndrome | Caused by colonic dysmotility or abnormal meconium consistency, leading to obstipation in the newborn. A contrast enema is both diagnostic and therapeutic. Some patients with meconium plug syndrome have Hirschsprung disease. |
| Functional ileus | Occurs in setting of prematurity, sepsis, respiratory distress, pneumonia, or electrolyte disturbances. |
| Small left colon* | Barium enema shows small-caliber left colon. Increased incidence with maternal diabetes. |
| Drugs administered to mother before delivery | Magnesium sulfate (MgSO4), opiates, or ganglionic-blocking agents. |
| Hypothyroidism | Infants with hypothyroidism also may have prolonged jaundice, lethargy, and low body temperature. |
| Other | Rare disorders associated with intestinal pseudo-obstruction, including megacystis-microcolon-intestinal hypoperistalsis (Berdon) syndrome. |
