This study will assess the diagnostic contribution of early abdominal ultrasound for acute abdomen in premature newborns.

Early ultrasound assessment would provide diagnostic assistance, in conjunction with clinical examination and biological testing, in the three main clinical situations encountered with an acute abdomen in premature infants: enterocolitis (digestive translocation of a bacterium secondary to inflammation, local fragility of the digestive tract, associated ischemic phenomena), reflex ileus (decrease in intestinal peristalsis secondary to peritoneal reactivity following inflammatory phenomena) and digestive immaturity (expressed by bloating, regurgitation, absence of spontaneous transit, related to the degree of prematurity).

Inclusion Criteria:

Premature under 37 weeks of amenorrhea with an adverse event of special interest such as :

• altered abdomen with bloating or presence of previsouly unknow marked collateral circulation,
• absence of spontaneous transit (> 48 hours),
• episode of rectal bleeding,
• repeated regurgitation/vomiting (during more than 50% of feedings),
• prolonged fasting (>12 hours), OR
• increase in cardiorespiratory events on continuous monitoring associated with one of the elements listed above.

Exclusion Criteria:

• organic malformation detected during prenatal monitoring or discovered in the immediate postnatal period,
• chromosomal abnormality detected during prenatal monitoring or discovered in the immediate postnatal period,- spontaneous perforation occurring during the first week of life.