Compare the bacterial digestive microbiota during the stay in neonatal intensive care between a group of premature newborns developing a NEC (necrotizing enterocolitis) and a group of newborns free from NEC.

Monitoring of a cohort of premature newborns with constitution of a collection of biological samples.

follow-up of newborns from birth up to 37 weeks of amenorrhea. The medical care of children will not be affected by their participation in the research.

• Sampling of amniotic fluid at the time of rupture of the water bag

• Sampling of the blood contained in the umbilical cord after clamping and section of the cord

• Sampling of meconium during the first 24 hours of life in intensive care / neonatal / maternity ward

• Collection of a daily stool sample until the end of hospitalization and when a NEC occurs

• Sampling of gastric residues during an episode of NEC

• Taking a daily sample of the newborn's enteral food

• Sampling of 500 µL of additional blood weekly during the punctures made for the treatment

• Daily statement of constants

• Record of all complications related to prematurity (HIV, bronchodysplastic, sepsis)

  • Blood analysis: CBC, platelets and CRP (data analyzed as part of the treatment). Specific analyzes for research will assess: the level of tryptase, IL4 and TLR4. The samples will be stored and analyzed in the immunology laboratory of the CHU Clermont Ferrand (Pr B. Evrard)
  • Analysis of the meconium sample and each stool emitted during hospitalization, and during an episode of ECUN

Inclusion Criteria:

• born prematurely < 37 weeks of amenorrhea at the maternity ward of the CHU
• affiliated with a social security regime
• the holders of parental authority are able to give an informed consent to participate in the research

Exclusion Criteria:

• fetal pathology
• newborns whose holders of parental authority are under guardianship or under the age of 18
• refusal of participation by holders of parental authority