Why are premies the ones who get necrotizing enterocolitis?

Not known: There are many theories but the answer to this question is not for certain.

Immature gut: Prematures have an immature gut that is more susceptible to decreased blood flow, infection, and other associated premature problems such as sepsis, premature lung disease, etc. Research is ongoing to try to isolate different causes so that they can be recognized early or prevented if possible.

Immature immune syst: Immature immune systems in the premature babies are likely mainly responsible for this serious infection that is nec (resulting from bacterial infvasion of the bowel wall).