Prevalence:

• 1 in 5,000 births.

Ultrasound diagnosis:

• Multiple fluid-filled loops of the bowel in the abdomen >7 mm in diameter presenting >25 weeks’ gestation.
• Distension of the abdomen with active peristalsis.
• If bowel perforation occurs, transient ascites, meconium peritonitis and meconium pseudocysts may ensue.
• Polyhydramnios >25 weeks’ gestation, especially in proximal obstructions.

Associated abnormalities:

• The incidence of chromosomal abnormalities and genetic syndroms is not increased.
• Other bowel anomalies: malrotation, gastroschisis, duplication and meconium ileus.
• 10% risk of cystic fibrosis (up to 90% in case of associated meconium peritonitis).

Investigations:

• Detailed ultrasound examination.
• Amniocentesis: DNA studies for cystic fibrosis if both parents are carriers.

Follow up:

• Ultrasound scans every 2-3 weeks to monitor growth and assess amniotic fluid volume. Amniodrainage may be necessary if there is polyhydramnios and cervical shortening.

Delivery:

• Place: hospital with neonatal intensive care and pediatric surgery.
• Time: 38 weeks.
• Method: induction of labor aiming for vaginal delivery.

Prognosis:

• The prognosis is related to the gestational age at delivery, the presence of associated abnormalities and site of obstruction. In those born after 32 weeks with isolated obstruction requiring resection of only a short segment of bowel, survival is >95%. Loss of large segments of bowel can lead to short gut syndrome, which is a lethal condition.

Recurrence:

• Isolated: no increased risk of recurrence.