Abnormal lipid metabolism has been proposed as a pathogenic factor of preeclampsia, although whether it is a constant feature in all preeclamptic patients is unclear. We assessed whether plasma triglyceride (TG) levels can distinguish a subgroup of preeclamptic women with alterations in lipoprotein profile from those with normal lipid metabolism and can be used to identify 2 distinct pathogenic groups in preeclampsia. This prospective study included 34 women with preeclampsia and 23 healthy pregnant women. Preeclamptic women were further subclassified into normal-TG (<250 mg/dL) and high-TG (>or=250 mg/dL) groups on the basis of the 90th percentile in our population. Low-density lipoproteins (LDLs) were ultracentrifuged and were separated into 4 subfractions, and lipid distribution in the subfractions was analyzed in all study groups. Vascular cell adhesion molecule-1 was also measured as a marker of endothelial dysfunction. Sixteen women with preeclampsia had high TGs (47% vs 13% in control subjects, P<.001). This subgroup showed a significant shift in lipid distribution, mainly, TGs, toward the small, dense LDL subfractions. However, preeclamptic patients in the normal-TG subgroup showed LDL subfraction lipid distribution similar to that of healthy pregnancies. Vascular cell adhesion molecule-1 levels were significantly elevated in preeclamptic patients in comparison with those in control subjects regardless of TG levels. The presence of a proatherogenic lipoprotein profile, previously described in preeclampsia, is characterized by increased small dense LDL and is exclusive to a subset of preeclamptic patients with high TG levels. These findings support the concept of heterogeneous pathogenic lines in preeclampsia and the use of subclassifications in pathophysiologic research on this condition.