<i>Cis</i>- and <i>Trans</i>-Isomeric Fatty Acids in Plasma Lipids of Newborn Infants and Their Mothers

The proportionate fatty acid composition of plasma lipids was determined by high-resolution gas-liquid chromatography in 30 pairs of mothers and their term infants at the time of birth. Trans-fatty acids were found at similar percentage levels in maternal and infantile plasma, evidence for the first time of their placental permeability. In umbilical plasma, linoleic and alpha-linolenic acids contributed markedly smaller portions to total fatty acids, in contrast to clearly higher proportions of their long-chain polyunsaturated metabolites (LCP). Significantly larger percentage values in cord than in maternal plasma were found for those LCP that are structural components of brain lipids, which may reflect a discriminating placental transport mechanism for certain physiologically important LCP.