40 years old 38 wks primigravida presented to training ultrasound unit of ESUOG at the mother of Egyptians hospital, for routine third trimester ultrasound, accidentally discoverd polyhyraminous and double bubble sign of duodenal atrasia no other anomalies detected by ultrasound.

Duodenal atresia (DA) is the commonest type of congenital small bowel obstruction usually presenting in the neonatal period. About half of fetuses with duodenal atresia have other associated anomalies, and these associations often contribute to morbidity and mortality. DA can be fatal unless promptly diagnosed and treated surgically. In experienced hands and in countries where prenatal ultrasound screening for anomalies is routine, DA can be confidently diagnosed prenatally, which can help in reducing the perinatal morbidity and mortality associated with diagnosis after delivery.

The prenatal diagnosis of duodenal atresia can be made sonographically by the demonstration of the fluid filled dilated stomach and duodenum, which gives the typical "double bubble" sign on ultrasound. Postnatally, the imaging diagnosis of duodenal atresia is usually first made on neonatal radiograph by demonstrating the same "double bubble" sign, which is due to a gas filled distended stomach and duodenal bulb.

Prenatal detection of DA helps in reducing the morbidity and mortality associated with late presentation.