(NEC) a serious disease affecting the bowel during the first three weeks of life; it is much more common in preterm babies. The abdomen distends and blood and mucus appear in the stools; the bowel may perforate. Treatment is to rest the bowel and administer antibiotics. If the bowel becomes necrotic, surgery may be necessary. The cause is unknown but the disease may be the result of a reduced supply of oxygen to the bowel or infection.