{'fraction_non_alphanumeric': 0.031982942430703626, 'fraction_numerical': 0.015991471215351813, 'mean_word_length': 5.659574468085107, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
The epidemiology and pathogenesis of neonatal necrotizing enterocolitis

Necrotizing enterocolitis (NEC) has been the most common gastrointestinal emergency in the preterm infant for almost 30 years, and yet remains one of the major unsolved problems of perinatal care. Clinically, NEC is characterized by the triad of abdominal distension, gastrointestinal bleeding and pneumatosis intestinalis on abdominal X-ray and its severity is assessed by Bell’s Staging System of Stage 1 (suspect), Stage II (definite) and Stage III (advanced).1 NEC predominantly affects preterm infants (90% of all cases), especially those <28 weeks gestation, less commonly term infants and rarely severely debilitated children. In the term infant it is almost universally associated with risk factors for gut ischaemia, such as congenital heart disease, perinatal asphyxia, Hirschsprung’s disease or an endocrine disorder.2 See related article, p 169 and 174.