With premature newborn increase survival, the risk of serious neonatal morbidity, such as necrotizing enterocolitis (NEC), also increased. NEC affects between 2 to 7% of premature infants including 5 to 22% of newborns weighing less than 1000 g.

NEC is an acquired disease, caused by inflammation of the intestinal lining. It is the most common life-threatening gastrointestinal emergency of prematurity, associated with a significant morbidity and mortality.

The etiology and physiopathology are multifactorial, complex, and remain poorly understood. The mechanism of the lesions seems to involve factors including immaturity of the intestinal barrier and the immune system, microvascular imbalance, disturbed gut flora and systemic inflammation.

Despite improved knowledge about this disease, the proportion of surviving patients has not improved for several years. It frequently leads to long-term sequelae depending on the severity of the NEC and its treatment.

Early diagnosis and early treatment of NEC may reduce the risk of mortality and morbidity. The aim of this retrospective bi-centric study is to look for risk factors allowing the prediction of NEC in order to prevent and improve the early management of this disease.

Inclusion Criteria:

• Premature newborns (< 37 weeks of gestation) having done a necrotizing enterocolitis stage II or III according to Bell's criteria.

Exclusion Criteria:

• Children term born (> 37 weeks of gestation)
• Necrotizing enterocolitis during an hospitalisation outside the NICU of Nancy or Lyon
• Malformation or pre-existing digestive pathology
• Complex or severe malformative pathologies

• Premature newborns (< 37 weeks of gestation) having done a necrotizing enterocolitis stage II or III according to Bell's criteria.
• Premature newborns (< 37 weeks of gestation) having grown up without nectrotizing enterocolitis at the same period of time, in order to associate 2 witness patient to one case patient.