The indications that motivated the decision to transfuse (or not) were analyzed to verify compliance with HAS recommendations. Medical records from 57 premature infants < 32 weeks hospitalized between 2016 -2017 were retrospectively analysed, especially all the events related to monitoring of hemoglobin level and RBC transfusions during the first month of life. The criteria (postnatal age, rate of haemoglobin, type of breathing assistance, oxygen needing, medullary regeneration) on which rely the decision process in the HAS algorithm for the RBC transfusion were also considered, as well as the final decision actually adopted for each case (transfused/ not transfused). All this made it possible to determine the kappa coefficient for evaluation of agreement with HAS new guidelines in the investigator's medical staff.

Inclusion Criteria:

• preterm infant hospitalized in Amiens School hospital (CHU Amiens-Picardie) between October 2016 and April 2017 during the first month of life, with allowed access on data recorded in medical files concerning the evolution of clinical characteristics (body weight,…) and the results of laboratory analyses performed during this initial hospital stay.

Exclusion Criteria:

• less than 25 weeks or more than 32 weeks at birth
• any hemoglobin dosage during the hospital stay
• serious congenital malformation
• known or documented neonatal red blood cell disease (inherited hemolysis, enzymopathy of red blood cell membrane,…)

preterm infant hospitalized in Amiens School hospital (CHU Amiens-Picardie) between October 2016 and April 2017 during the first month of life