The bubble sign in the gasless abdomen of the newborn.

The bubble sign (BS) in the gasless abdomen of the newborn is a helpful clue in the diagnosis of an upper gastrointestinal obstruction. The already swallowed air serves as the natural contrast agent. The single, double and triple BS are described in view of 23 cases indicating the level of the obstruction, and its differential diagnosis is discussed. The presence of BS in the gasless abdomen of the newborn is an indication for surgery until proved otherwise. With the increasing experience by ultrasonography, this modality should be considered as the first bed-side procedure when suspecting upper gastrointestinal obstruction, and then be confirmed by radiograms.