INTRODUCTION: At the Department of Neonatology at Rigshospitalet, Copenhagen, Denmark, decades of extensive use of mother's milk and human donor milk should theoretically limit the incidence of necrotising enterocolitis (NEC) among very low birth weight infants. The aim of this study was to determine our local incidence of NEC from 1996 to 2009.

METHODS: The data in departmental clinical database containing information about admissions in the 1996-2009 period was compared with data in the Danish Patient Registry. Inconsistencies were resolved by reviewing the clinical records. The population of interest was infants inborn at Rigshospitalet with an age of 0-1 days on admission.

RESULTS: A total of 8,893 infants were included in the study and 1,843 (20.7%) weighed less than 1,500 g at birth. NEC occurred in 111 of these (6.0%). The incidence ranged from 20.5% in the 500-599 g birth-weight group to 0.5% in the 1,200-1,299 g birth-weight group. There was no trend over time in the incidence of NEC (b = -0.02/year (95% confidence interval: -0.59; 0.55, p = 0.98) and no evidence of a higher frequency of NEC in certain months or certain seasons (p = 0.52 and p = 0.32).

CONCLUSION: Our incidence of NEC was close to average compared with incidences reported in international literature. There was no suggestion of an epidemic cause or that the incidence was decreasing. Considering the impact of NEC on the individual infant, it is important to keep searching for new ways to reduce the problem.

FUNDING: not relevant.

TRIAL REGISTRATION: The study was approved by the Danish Data Protection Agency.