An atresia refers to a birth defect that causes an obstruction of the digestive tract in the newborn. It occurs when the intestine, which should be an open tube, closes off in one or more places, and can affect any part of the gastrointestinal tract, from the oesophagus, small bowel down to the colon. These obstructions cause a blockage or narrowing of the bowel, preventing food and faeces from moving through the body as they should. Some common symptoms include abdominal swelling and vomiting. The digestive tract blockage is repaired surgically, and the procedure is performed soon after birth.