Background: Preterm infants are at increased risk for DHA deficiency because from 26th weeks of pregnancy until term, 80% of the brain this acid accrues in the fetus. Moreover, the main sources of lipids for preterm newborns are fat emulsions which do not contain DHA.
Aim: 1) to investigate the plasma DHA concentration in prematurely delivered newborns who are receiving a fish-oil emulsion in amount equal to one third of total daily intravenous lipid intake or soybean/olive oil fat emulsion from the first day of life. 2) to compare plasma DHA concentration, evaluated immediately after birth in prematurely born infants, with the respective data obtained in full term newborns.
Materials and methods: Twenty one preterm infants in the two groups: the study group n=12 (newborns fed parenterally with a partially replaced a soybean/olive oil emulsion with a fish-oil emulsion); the control group n=9 (newborn fed parenterally with a soybean/olive oil emulsion) comparable with regard to demographic and clinical characteristics. Determination of plasma and erythrocytes DHA concentrations in newborns was made using a high-performance liquid chromatography-mass spectrometry (LC-ESI/MS) method. Detection of parent ions with negative ionization mode, m/z 327,5 amu. Method validation was according to the ICH and FDA requirements.
Results: The mean values of plasma DHA level measured on the 7th, 14th, 21st, 28th day of life, were statistically significantly lower in the control group when compared with respective data obtained in the study group (7th day: 7.98 vs 42.4 ěmol/L, p=0.0002; 14th day: 6.8 vs 21.14 ěmol/l, p=0.000001; 21st day: 11.56 vs 19.1 ěmol/L, p=0.035; 28th day: 11.4 vs 25.4 ěmol/L, p=0.0004). The mean value of plasma DHA level in full-term newborns measured in the first hours of life was 164.7 ěmol/L whereas in preterm neonates it reached 15.9 ěmol/L (p=0.000001).
Conclusions: The administration of fish-oil-based fat emulsion as a component of total parenteral nutrition from the first day of life may alleviate a marked decrease in plasma DHA level observed in preterm infants within the first weeks after birth. Established method allows for routine determination of DNA concentrations in plasma erythrocytes of newborns.