Prematurely born infants are at risk for necrotizing enterocolitis (NEC), the most common gastrointestinal emergency encountered in the newborn intensive care unit. This disease occurs in between 5 - 10% of infants born at less than 30 weeks gestation or less than 1500 grams birth weight. In these patients, NEC routinely develops during the 3rd or 4th week of life. NEC rarely occurs in infants born closer to term; for these patients NEC usually develops during the 1st week of life. So far, no one has explained the inverse relationship between gestational age at birth and the delay in NEC development.