To study the relationships between the essential fatty acid (efa) composition of maternal diet, maternal efa status and the efa status of healthy newborn infants.a prospective longitudinal study was performed in which 176 pregnant women completed a food frequency questionnaire (ffq) before 13, at 22, and at 32 weeks of gestation, so that changes in nutrient intake throughout pregnancy could be recorded. Around 22 weeks, a dietary history was performed and a maternal blood sample was collected. Immediately after delivery, a blood sample from the umbilical vein and a piece of the umbilical cord were collected. Fatty acid compositions were determined for phospholipids (pls) isolated from maternal and umbilical plasma and from umbilical vein and artery vessel walls.no significant differences in the mean daily intake of total fat, saturated fat, mono-unsaturated fat, polyunsaturated fat and linoleic acid (18:2(n-6), la) were observed between the three trimesters. Maternal la intake was positively associated with la levels in maternal and umbilical plasma and negatively associated with 20:3(n-9), 18:3(n-3), 20:4(n-3) and 22:5(n-3) levels in maternal plasma, with 20:5(n-3) levels in umbilical plasma and with 22:6(n-3) levels in umbilical vein vessel walls. Significant positive correlations for almost all (n-6) and (n-3) fatty acids were observed between maternal and umbilical plasma levels.the maternal dietary fat composition appears to be consistent during pregnancy. A high maternal la intake may have a lowering effect on the maternal as well as on the neonatal (n-3) fatty acid status. Finally, neonatal efa status is strongly related to maternal efa status.