Is Necrotizing Enterocolitis a Post-Maturity Syndrome?
No, necrotizing enterocolitis (NEC) is definitively a disease of prematurity, not post-maturity—it primarily affects premature infants and the risk is inversely proportional to gestational age.
NEC as a Disease of Prematurity
- NEC overwhelmingly affects preterm infants, with more than 85% of all cases occurring in very low birth weight or very premature infants 1
- The incidence demonstrates a clear inverse relationship with gestational age: 10-20% in infants born at 23-24 weeks' gestation, 5-10% at 25-27 weeks' gestation, and less than 5% at ≥28 weeks' gestation 2, 3
- Among very low birth weight infants (<1500g), the incidence ranges from 6-10% 4, 5
Age of Onset Pattern
- The age of onset is inversely related to postmenstrual age at birth, meaning the more premature the infant, the later NEC typically develops 1
- This pattern reflects the underlying pathophysiology related to intestinal immaturity rather than any post-maturity process 4
Rare Occurrence in Term Infants
- NEC is less common in term and late preterm infants 1
- When NEC does occur in term infants, it is commonly associated with congenital heart disease or other anomalies, representing a distinct pathophysiologic entity from preterm NEC 1
Pathophysiologic Basis
- The fundamental etiology is structural and immunological intestinal immaturity characteristic of prematurity 4
- In preterm infants with immature gastrointestinal tracts, NEC development involves colonization with pathogenic bacteria, secondary ischemia, genetic polymorphisms, and altered intestinal barrier function 4, 5
- The altered microbial colonization patterns in premature infants contribute to increased vulnerability to NEC compared to term infants 6