After birth, in the presence of risk factors for early neonatal bacterial infection (IBNP), the pediatrician must make a difficult decision quickly or not to prescribe additional examinations and / or hospitalize or not the newborn in order to administer parenteral antibiotics. This decision takes into account several contextual data, (clinical, biological and bacteriological clinical data) to be considered simultaneously. These information lack sensitivity and specificity.

Therefore, the common attitude among newborns in many countries remains the achievement of a significant number of additional tests and the establishment, without a prior evidence of infection, intravenous empirical antibiotic therapy for 48 -72h at least in hospitalization. However, the diagnosis of IBNP posteriori, is often reversed. This attitude is:

1. one source to higher health care costs (hospitalization, additional examinations)
2. Selection of the bacterial ecology of the newborn and neonatal services and
3. stress for the newborn and parents

Inclusion Criteria:

• Birth to motherhood.
• Term > 34 weeks .
• Presence of at least one of the factors of major or minor infection risk

Exclusion Criteria:

• cord blood sample unavailable.
• Death in the delivery room
• Corticosteroids prenatally (modification of cytokine production ) .