Up-to-date, the preterm newborn nutrition is based on human breast milk or it's imitations. However, the growth rate is known to be reduced compared to the fetal growth rate. In order to attempt a better growth rate of the preterm newborn infants it is important to evaluate the metabolic components of the fetal blood and try to find components that might influence its growth.

Little is known of the metabolic components of the fetal blood, including amino acid profile. The aim of the study is to evaluate amino acid profile in the fetus blood in different gestational ages and compare it to post natal period.

Inclusion Criteria:

• All new-born infants 5 of each gestational age

Exclusion Criteria:

• none

Term and preterm newborn infants