Impact of gestational age on the clinical presentation and surgical outcome of necrotizing enterocolitis

Objective: This investigation tests the hypothesis that the clinical presentation and the outcome of necrotizing enterocolitis (NEC) vary with gestational age (GA). Methods: All infants admitted to our center between October 1991 and September 2003 were evaluated weekly to identify confirmed cases of NEC. Based upon GA, these infants were divided into five groups: Extremely premature (EP, 23 to 26 weeks), very premature (VP, 27 to 29 weeks), moderately premature (MP, 30 to 34 weeks), near-term ( NT, 35 to 36 weeks), and term ( T, 37 to 42 weeks). Results: A total of 202 infants developed NEC. The most common sign of NEC among EP infants was ileus (77%), followed by abdominal distention (71%), emesis (58%), pneumoperitoneum (54%), fixed intestinal loop (52%), gasless abdomen (42%) and bloody stools (17%). Intramural gas was detected in 100% of T but was present in only 29% of EP infants (P< 0.0001). Similarly, portal venous gas was common in T but infrequent in the EP infants ( 47 vs 10%, P< 0.0001). Despite a higher peritoneal drain insertion rate ( 31 vs 5%, P< 0.001) and a higher mortality rate ( 33 vs 10%, P = 0.05) in EP compared to T infants, other clinical outcomes were not different. Conclusions: The clinical presentation of NEC is different in EP compared to more mature infants; however, outcome among NEC survivors is similar across all GA. Reliance solely on observation of intramural or on portal venous gas in EP infants may lead to a delay or failure in the diagnosis.