['Preeclampsia is characterized by enhanced platelet aggregation and vasoconstriction and is related to an elevated ratio of thromboxane A2 to prostacyclin I2.', 'We investigated whether altered eicosanoid production in preeclamptic women could be explained by the fatty acid composition of umbilical vessel walls and platelets.', 'The fatty acid composition of maternal and umbilical platelets and of umbilical arteries and veins in 27 preeclamptic women and 24 normotensive women was determined. Between-group differences were analyzed with linear discriminant analysis, the Kruskal-Wallis test, or analysis of covariance with gestational age as the covariate.', 'Platelets of preeclamptic women contained lower amounts of 20:5n-3 and a higher ratio of 20:4n-6 to 20:5n-3 than did platelets of normotensive women. Additionally, linear discriminant analysis revealed higher amounts of 20:4n-6 in platelets of preeclamptic women. Umbilical arteries and veins in preeclamptic women contained lower amounts of long-chain polyunsaturated fatty acids (PUFAs) of the n-3 series, n-6 long-chain PUFAs, and 20:3n-6 than did umbilical arteries and veins of normotensive women. Umbilical arteries also had lower amounts of 20:4n-6, higher amounts of 20:3n-9, and a higher ratio of 20:3n-9 to 20:4n-6.'] Do umbilical vessels of preeclamptic women have low contents of both n-3 and n-6 long-chain polyunsaturated fatty acids?