<prompt> In case of new born the commonest cause of intestinal obstruction is -Annular pancreasDuodenal AtresiaJejunal atresiaOesophageal atresia  <response>: Congenital atresia and stenosis are the commonest cause.The incidence of atresia varies with anatomical site:duodenum - 35percentjejunum - 15percentileum - 25percent ascending colon - 10percentmultiple sites - 15percentVomiting is bile stained or not, depends on the atresia proximal or distal to ampulla of vater. In 85 of cases the atresia is distal to the ampulla, therefore the vomiting is bilious.Approximately 13 of newborns with duodenal atresia have associated Downs syndrome.The double bubble seen on the air contrast upper GI series is characteristic of duodenal atresia.Treatment of choice is - Duodenoduodenostomy 