Enteropathy and necrotizing enterocolitis (NEC) are digestive emergencies in premature neonates which represent a major concern for the vital prognosis. It is therefore important to propose a tool for early diagnosis of these intestinal complications in order to avoid extended interruptions of enteral feeding at a period of life where growth (and digestive maturation) is in the foreground. Currently, the diagnosis of digestive impairment is based on classical clinical, biological (CRP, procalcitonin, fecal calprotectin, NFS) and radiological (abdomen without preparation) approaches, which induce on one hand a prolonged interruption of enteral feeding sometimes useless and even harmful for the intestinal maturation and, secondly, the establishment of a parenteral nutrition which is not risk-free. The study propose to dose the fecal calprotectin, a non-invasive marker of digestive inflammation, in order to validate the threshold decision proposed in a pilot study (350 µg/g of feces). Measurement of fecal calprotectin levels will be used as an integrated tool to build a powerful screening score combined to the usual parameters used in routine care for the diagnosis of and enteropathy and necrotizing enterocolitis (NEC) in premature neonates. A cohort of preterm infants born at a gestational age of 33 weeks or less will be included from birth. A stool sample will be collected from the diaper once a week, from birth until discharge from the hospital, and every day during gastrointestinal events (interruption of enteral feeding over 48 hours). The study will evaluate the performance of the rapid assay of fecal calprotectin by quantitative immunochromatography compared to the reference method by enzyme-linked immunosorbent assay (ELISA).