Visceral fat accumulation stimulates the production of adipocytokines in patients with metabolic syndrome. Excess body weight gain during pregnancy is a risk factor for preeclampsia. To evaluate whether the pathogenesis of preeclampsia is similar to that of metabolic syndrome, we measured plasma adipocytokine concentrations and investigated the association between plasma adiponectin concentrations and body weight gain or endothelial function in preeclamptic women. We investigated 15 preeclamptic and 17 women with uncomplicated pregnancies. Women with preeclampsia had significantly lower plasma concentrations of adiponectin (10.2+/-2.0 vs. 7.3+/-2.2 microg ml(-1), P<0.01), but higher concentrations of leptin, plasminogen activator inhibitor-1, interleukin-6, vascular cell adhesion molecule-1, E-selectin and C-reactive protein. Plasma triglyceride levels were significantly higher in preeclamptic patients, but the levels of other lipids did not differ significantly between the two groups. We found that flow-mediated vasodilation was significantly decreased in preeclamptic women compared with controls (10.6+/-6.4 vs. 3.8+/-2.0%, P<0.001). Plasma adiponectin concentrations correlated negatively with body mass index (r=-0.50, P<0.05) and body weight gain during pregnancy (r=-0.63, P<0.01), and positively with flow-mediated vasodilation (r=0.50, P<0.05) in preeclamptic women, but not in women with uncomplicated pregnancies. Similar to the patients with metabolic syndrome, we found that dysregulation of adipocytokines, such as low adiponectin levels and high levels of other adipocytokines, and excess body weight gain during pregnancy, may decrease plasma adiponectin concentrations that are associated with endothelial dysfunction in preeclamptic women.