Necrotizing Enterocolitis

National Organization for Rare Disorders, Inc.

Skip to the navigation

It is possible that the main title of the report Necrotizing Enterocolitis is not the name you expected.

Disorder Subdivisions

  • None

General Discussion


Necrotizing enterocolitis, abbreviated NEC, is a devastating disease that affects a newborn's intestines. It typically occurs in premature infants, born less than 37 weeks, and is characterized by severe inflammation of a baby's small or large intestines, which may progress to tissue death (necrosis). NEC occurs in about 1 case per 1000 live births [1]. NEC can occur in full term babies but it is much more common in very premature infants, especially very low birth weight babies — incidence ranges from 3% in infants with birth weight of 1251 to 1500 grams (2 pounds 12.13 ounces to 3 pounds 4.91 ounces) to 11% for infants born weighing less than 750 grams (1 pounds 10.46 ounces) [2]. NEC typically occurs when a newborn is several weeks old and on enteral feeds. Initially babies present with vomiting, large distended belly, bloody stools, long pauses in their breathing, and decreased activity. This can further progress to bowel necrosis and perforation. Medical treatment involves discontinuation of enteral feeds (the delivery of nutritionally complete feeds directly into the stomach), initiation of broad-spectrum antibiotics and supportive care [3]. Surgical intervention is indicated when there is evidence of bowel perforation and necrotic bowel. This serious gastrointestinal disease is associated with significant morbidity (complications associated with the disease) and mortality. Despite treatment, about 15% of babies who develop NEC die and some babies that survive suffer from numerous complications such as short bowel syndrome, poor growth, and long-term neurodevelopmental impairments [4]. The exact mechanism of this disease, while not fully understood, is believed to be multifactorial and related to a premature intestine, abnormal gut microbial colonization, and intestinal inflammation.

NEC remains a leading cause of morbidity and mortality in the neonatal intensive care unit despite significant advances in the care being provided to premature infants [5;6]. It remains primarily a disease of prematurity. Term infants with risk factors such as congenital heart disease, sepsis, or hypotension (low blood pressure) can also develop NEC [7]. Bell's classification was introduced in 1978 and is still widely used to clinically stage NEC based on disease severity: stage I being suspected NEC, stage II being confirmed NEC, and stage III being confirmed NEC with intestinal perforation and/or multi-system involvement [8]. More recently, the terminology of acquired neonatal intestinal diseases (ANIDs) was introduced by Gordon et al. to further classify NEC into subgroups based on associated clinical factors: these include NEC in term infants, NEC associated with red blood cell transfusions, NEC associated with cow's milk intolerance, NEC associated with contagion and/or lymphocytosis, NEC associated with extreme prematurity, and NEC-like diseases [9].

Supporting Organizations

The Morgan Leary Vaughan Fund, Inc.

PO Box 2488
Milford, CT 06460
Tel: 203-606-4873

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report.

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

Last Updated:  5/14/2015
Copyright  2015 National Organization for Rare Disorders, Inc.