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Gastrointestinal Tract | Duodenal or intestinal atresia

Duodenal and intestinal atresias are fetal bowel obstructions. They can occur at any point along the gastrointestinal tract (bowel). Whether or not the obstruction is a serious threat to the health of the fetus depends on where it is located, what caused it, and whether there are other abnormalities associated with it.

Essential Information

  • The incidence of fetal bowel obstruction is about 1 in 2,000 pregnancies.
  • Fetal bowel obstruction may be either an isolated finding, or may be associated with several conditions including genetic disorders (e.g. chromosomal disorders or cystic fibrosis), fetal structural abnormalities, or fetal infections (e.g. cytomegalovirus (CMV)).
  • In many cases, the exact type of bowel obstruction cannot be accurately determined until after birth. In many cases, the outcome is excellent.


The diagnosis of fetal bowel obstruction is usually made when dilated bowel loops are noted on ultrasound examination. They can show up on a routine ultrasound or as part of an investigation for a condition called fetal polyhydramnios (an abnormally increased amount of amniotic fluid).

Ultrasound is done to determine the site of the obstruction and whether there are other abnormalities. Genetic studies may be conducted, as well as testing for fetal infection.

There are many different locations along the gastrointestinal tract where a fetal bowel obstruction can occur. The main causes/locations of bowel obstruction are as follows:

  • Esophageal atresia (obstruction at the level of the esophagus)
  • Pyloric atresia (obstruction at the outlet of the stomach)
  • Duodenal atresia (obstruction in the small bowel immediately beyond the stomach)
  • Small bowel atresia (obstruction anywhere in the small bowel)
  • Meconium ileus (obstruction of the small bowel by unusually thick fetal stool)
  • Volvulus (obstruction of the bowel due to twisting of bowel loops around each other)
  • Hirschprung’s disease (malfunction of the large bowel)
  • Anal atresia (obstruction at the level of the anus)


Because fetal bowel obstructions can have so many locations and causes, neonatal treatment varies.

Referral Information

All patients with suspected duodenal or intestinal stenosis or atresia should be referred to a tertiary care centre, such as Mount Sinai Hospital, for evaluation.