Necrotizing enterocolitis in term neonates: data from a multihospital health-care system

Objective: In the past 5 years, 30 term or near-term neonates in the Intermountain Healthcare system developed necrotizing enterocolitis (NEC) Bell's stage >= II. We sought to identify possible explanations for why these patients developed NEC, by comparing them with 5847 others that did not develop NEC, from the same hospitals and of the same gestational ages, cared for during the same 5 - year period. Study design: Data were collected from neonates admitted to any of the Intermountain Healthcare NICUs with a birth date from 1 January 2001 to 30 June 2006, and a gestational age > 36 weeks. A variety of patient features and feeding practices were compared between those that did vs did not develop NEC. Result: Forty-one neonates > 36 weeks gestation were listed in the discharge records as having NEC of Bell's stage II or higher. However, on review of these 41 medical records, 11 were seen to have had NEC of Bell's stage I, whereas the remaining 30 had radiographs and clinical courses indicative of Bell's stage > II. Those 30 formed the basis of this study. Twenty-eight of the 30 developed NEC after having been admitted to an NICU for some other reason; the other two developed NEC at home, within 2 days of being discharged from an NICU. The 30 that developed NEC were more likely than the 5847 that did not develop NEC, to have congenital heart disease ( P = 0.000), polycythemia ( P = 0.002), early-onset bacterial sepsis ( P = 0.004) or hypotension ( P = 0.017). All 30 received enteral feedings before NEC developed; 29 were fed either artificial formula or a mixture of formula and breast milk. The one that was exclusively fed human milk was fed human milk with added fortifier ( 24 cal/oz). The 30 that developed NEC were more likely to be fed formula exclusively (P = 0.000). Seven of the 30 had a laparotomy for NEC; two of the seven had total bowel necrosis and support was withdrawn. The other five had perforations and bowel resections. The mortality rate was 13% (4/30). Conclusion: In our series, NEC among term or near-term neonates was exclusively a complication developing among patients already admitted to a NICU for some other reason. We speculate that the combination of reduced mesenteric perfusion and feeding with artificial formula were factors predisposing them to develop NEC.