Duodenal atresia occurs when the small bowel does not form properly during fetal development. A blockage forms, preventing the contents in the stomach to pass through.
This is the most common type of congenital small bowel narrowing, affecting approximately 1 in 10,000 births. Additional structural abnormalities are common and may involve the heart, kidneys, skeleton, or other regions of the intestines. Chromosomal abnormalities and genetic syndromes may be associated, with approximately one-third of duodenal atresia cases diagnosed with Down syndrome.
Duodenal atresia is suspected when a “double bubble” sign is identified at the anatomy ultrasound performed between 16 and 20 weeks of gestation. Once noted, additional imaging is recommended, including fetal echocardiography. Consultation with a genetic counselor is recommended to discuss available methods of genetic testing. These include non-invasive screening tests of maternal blood and invasive procedures such as amniocentesis. Consultations with neonatologists and pediatric surgeons are recommended during the pregnancy to discuss prognosis and management after birth.
The prognosis for duodenal atresia depends largely on the presence of associated structural and genetic abnormalities. In cases of isolated duodenal atresia, successful surgical repair is possible in nearly all cases with an excellent outcome. However, a small bowel obstruction impairs the fetus’ ability to swallow amniotic fluid and may result in accumulation of excess amniotic fluid within the uterus. This condition, referred to as polyhydramnios, increases the risk of going into labor or rupturing membranes (“breaking your water”) in the preterm period (less than 37 weeks). Prognosis for the infant would then be complicated by illnesses associated with preterm delivery.