Duodenal atresia is a congenital malformation in which the duodenum, the first portion of the small intestine, is completely or partially obstructed. On prenatal ultrasound, the classic finding is the double bubble sign, showing the distended stomach and proximal duodenum as two side-by-side, fluid-filled structures in the upper fetal abdomen. Polyhydramnios, or excessive amniotic fluid, often accompanies this finding because the fetus cannot swallow and absorb amniotic fluid normally when the intestine is blocked. Duodenal atresia has a strong association with Down syndrome and other congenital anomalies, so its detection on ultrasound prompts a thorough evaluation for associated conditions and genetic counseling.
Sonography Term