IUGR (intrauterine growth restriction) increases the incidence of perinatal complications and, although several placental transport functions have been shown to be altered in pregnancies complicated by IUGR, the mechanism behind it is not well understood. The aim of the present study was to investigate factors in maternal and cord blood plasma from normal and IUGR-complicated pregnancies associated with the body weight of newborns. At the time of Caesarean section, 24 women with IUGR pregnancies were compared with a group of 30 normal controls with AGA (appropriate gestational age) fetuses who were studied at Caesarean section, which took place 5 weeks later than IUGR pregnancies, and also to a group of 25 non-delivered gestational agematched control pregnant women (AGA-35wk). Maternal plasma retinol, γ - and α-tocopherol, NEFAs (non-esterified fatty acids), and palmitic, palmitoleic, γ -linolenic and arachidonic acids were higher in women with IUGR pregnancies than in AGA-35wk controls, whereas stearic and α-linolenic acids were lower. Smaller differences were found when comparing these variables for IUGR and AGA women. However, umbilical vein plasma γ -tocopherol, cholesterol, triacylglycerols and NEFAs were higher in the IUGR group than in the AGA group, whereas arachidonic acid was lower. Maternal plasma retinol and NEFAs were the only variables negatively correlated with birthweight when multiple linear regressions were analysed. In conclusion, the increased levels of circulating retinol and NEFAs in maternal plasma are negatively associated with birth and placental weights, which may reflect an impaired placental transfer in IUGR pregnancies. As retinoids are involved in the control of gene transcription, it is proposed that a decrease in placental transfer of retinol could underlie the metabolic dysfunction of IUGR pregnancies.