Changes in the fatty acid composition of plasma and red blood cell membrane during the first hours of life in human neonates.

The objective of this work was to examine the changes in the fatty acid profiles of plasma lipid fractions and red blood cell membrane phospholipids in newborn infants during the first 6-8 h of life. Methyl esters of fatty acids from plasma free fatty acids and phospholipids and from membrane phosphatidylethanolamine, phosphatidylcholine and sphingomyelin for cord blood (n = 20) and venous blood (n = 19) were analyzed by GLC. Important changes were observed in plasma fatty acids. Palmitic and palmitoleic acid increased from birth to 6-8 h of age for both free fatty acids and phospholipids. Palmitic acid also increased in membrane phosphatidylcholine and phosphatidylethanolamine. In the former, stearic acid declined whereas oleic and docosatetraenoic acids increased. Phosphatidylethanolamine and sphingomyelin were less affected than phosphatidylcholine probably because the internal location of the two first fractions in erythrocyte membrane. Polyunsaturated fatty acids dropped slightly during the first hours of life in most lipid fractions. This may be a consequence of the interruption of placental fatty acid supply and the limited capacity of the newborn to desaturate their essential fatty acid tissue stores.