While the causes of NEC are unknown, researchers believe that a decrease in blood flow to the bowel keeps the bowel from producing the mucus needed to protect the gastrointestinal tract, so when feedings start and the food moves into the weakened section of the intestinal tract, bacteria from the food damages the intestinal tissue, leading to tissue death, perforation of the intestine and severe infection in the abdomen.
Most of the time, this condition develops in sick or premature infants, usually when the infant is still in the hospital. Babies most at risk for NEC include:
- Premature infants
- Infants fed concentrated formulas
- Infants in a nursery where there has been an outbreak of NEC
- Infants who received blood exchange transfusions
- Babies with gastrointestinal infections
NEC is much less common in infants who are given human milk, and is rare is babies who have not received feedings. Additionally, the fact that NEC sometimes occurs in “epidemics”—i.e., in several babies in the same nursery—indicates that it may in some cases be spread from baby to baby, even though all nurseries have strict precautions aimed at preventing the spread of infection. On the other hand, this may be coincidental.