Does nec only happen to premature babies?

No. Necrotizing enterocolitis (nec) is a serious intestinal problem that occurs in some premature babies. Nec can happen, but is much less common, in full-term babies. In nec, a combination of decreased blood flow to the intestines plus infection of the intestines with bacteria, leads to severe damage to parts of the intestines. Surgical removal of some damaged intestines must be done in some cases.
No. Majority of nec occur in premature babies, however, it can also occur in full term babies.
No. Although nec is seen much more frequently in premature babies it can occur in full term newborns as well.