Epidemic occurrence of neonatal necrotizing enterocolitis.

In case-control studies of three epidemics of neonatal necrotizing enterocolitis (NEC) in three different high-risk nurseries in three states, no particular risk factor was associated with affected infants or their mothers. Epidemic cases had higher birth weights and Apgar scores and fewer perinatal difficulties than those previously reported for sporadic cases. Seven infants fed primarily breast milk were not protected against disease. Early antibiotic therapy was associated with a significantly decreased risk of disease in one outbreak. In two hospitals, affected infants who received antibiotic therapy during the first three days of life had a significantly later disease onset. The occurrence of the disease in epidemics and the decreased risk or modification of disease with antibiotic therapy support an infectious etiology for NEC.