title: Epidemiology of necrotizing enterocolitis--Part I: Changing regional trends in extremely preterm infants over 14 years.
abstract: OBJECTIVE
  Advances in perinatal care include exogenous surfactant, unequivocal acceptance of antenatal steroids and in utero and ex utero transfers to tertiary centres. Increased survival of extremely premature infants may change the incidence and outcome of necrotizing enterocolitis (NEC). Our aim was to examine the trends in the incidence of NEC, surgery and mortality in infants of 24-28 weeks gestation in a retrospective regional review of three epochs over a span of 14 years.
  
  
  METHODS
  Radiologically or surgically proven NEC cases were determined from the New South Wales Neonatal Intensive Care Unit Study database. Three epochs were examined. A total of 360 infants were admitted in 1986-87 (Epoch 1), 622 in 1992-93 (Epoch 2) and 673 in 1998-99 (Epoch 3).
  
  
  RESULTS
  There was an increase in neonatal intensive care unit admissions and a decrease in early and overall mortality of these very premature infants across the epochs. None of the early deaths was due to NEC. The incidence of NEC decreased in post day 5 survivors: 33 cases in Epoch 1 (12%), 60 cases in Epoch 2 (12%) and 34 cases in Epoch 3 (6%, P < 0.001). There was no change in surgical intervention (45%, 57% and 41%, respectively) or mortality due to NEC (37%, 27% and 32%). The reduced incidence of NEC was not singularly influenced by antenatal steroids, exogenous surfactant or outborn delivery. In a multivariate analysis, only later epoch of birth was independently associated with reduced NEC risk.
  
  
  CONCLUSIONS
  With improved care and survival of extremely premature infants, the incidence of NEC has decreased, but it remains a disease of high mortality and morbidity.
authors.affiliation: School of Women's and Children's Health, University of New South Wales, Australia.
authors.forename: Melissa
authors.initials: M
authors.lastname: Luig
authors.forename: Kei
authors.initials: K
authors.lastname: Lui
mesh_terms: D020345:Enterocolitis, Necrotizing / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy; D005260:Female; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D008423:Maternal Age; D009517:New South Wales / Q000453:epidemiology; D012189:Retrospective Studies