Swelling, tenderness and redness of the intestine caused by an infection or decreased blood supply to the intestine. NEC may injure or destroy parts of the bowel. The seriousness of NEC is variable. It may affect only the innermost lining or the entire thickness of the bowel. Premature babies, especially those who are born small for gestational age or who are twins, are at greater risk for NEC than babies who are born at full-term.