As extremely low birth weight infants are high-risk patients, the study aimed to compare neonatal care, nutritional strategy and postnatal growth of these infants in two European neonatal units. A retrospective study included extremely low birth weight infants born in Lyon, France or in Stockholm, Sweden. Data on morbidity, treatments, care practices, macro-nutrient intakes and postnatal growth were collected to determine risk factors of extra uterine growth restriction at discharge.

By comparing postnatal growth in ELBW infants hospitalized in two European neonatal intensive care units with different nutritional and extra nutritional care,our objective was to evaluate the role of nutrition in this population of preterm infants.

In a retrospective study, all ELBW infants (birth weight under 1000 g) with a gestational age between 23 and 28 weeks were included if they were admitted during the first 24 hours of life and stayed for at least seven weeks in two European units (Lyon, france, and Stockholm, Sweden). Parenteral and enteral nutrition policies were detailed and protein and energy intakes were collected.Growth assessment Postnatal growth was precisely evaluated and compared in the two groups of infants.

Body weight, crown-heel length and head circumference were measured in both units at birth and until discharge. We calculated z-scores and changes in z-scores between birth and 36 weeks post-conceptional age (delta z-score) for body weight, HC, and crown-to-heel length using Olsen's references. Intra-uterine growth restriction was defined as a birth weight below or equal to minus two standard deviations. Extra-uterine growth restriction was defined as a z-score loss above or equal one standard deviation between birth and 36 weeks PCA. I

Inclusion Criteria:

• birth weight under 1000 grams
• gestational age (GA) between 23 and 28 weeks
• born in 2012
• admitted during the first 24 hours of life
• stayed in one of the two studied units for at least 7 weeks before transfer to the referring hospital, discharge to home or death.

Exclusion Criteria:

• Neonates with congenital anomalies

Extremely low birth weight infants born in two European tertiary care centres: neonatal unit of Croix Rousse Hospital in Lyon, France and the neonatal unit of Astrid Lindgren Children's Hospital in Stockholm, Sweden