Essential fatty acid composition of plasma phospholipids and birth weight: a study in term neonates.

BACKGROUND Essential fatty acids (EFAs) in umbilical cord blood samples are associated with attained birth weight in premature infants and low-birth-weight neonates. OBJECTIVE The objective was to investigate relations between the EFA composition of cord and maternal plasma phospholipids and birth weight in term neonates. DESIGN This was a cross-sectional study in 627 singletons born at term. The plasma phospholipid EFA composition of the mothers was determined by gas-liquid chromatography at study entry (< or = 16 wk gestation), at delivery, and in cord plasma at birth. Birth weights were normalized to SD scores. RESULTS In cord plasma, the dihomo-gamma-linolenic acid concentration was positively related to weight SD scores. Both arachidonic acid (AA) and docosahexaenoic acid (DHA) were negatively related to weight SD scores. EFA-status indicators showed similar negative associations, whereas eicosatrienoic acid concentrations were positively related to neonatal size. In maternal plasma, proportions of n-3 long-chain polyenes (LCPs) and n-6 LCPs decreased during pregnancy. Larger decreases in AA, DHA, n-3 LCP, and n-6 LCP fractions were observed in mothers of heavier babies. Higher concentrations of LCPs in maternal plasma were, however, not related to a larger infant size at birth. CONCLUSIONS A lower biochemical EFA status in umbilical cord plasma and a larger decrease in maternal plasma LCP concentrations are associated with a higher weight-for-gestational-age at birth in term neonates. Our findings do not support a growth-stimulating effect of AA or DHA; however, they do suggest that maternal-to-fetal transfer of EFAs might be a limiting factor in determining neonatal EFA status.