Objective: The prototypic long pentraxin pentraxin 3 is a new candidate marker for inflammatory conditions reflecting the involvement of the vascular bed. Endothelial dysfunction is a prominent feature of preeclampsia as a result of excessive maternal systemic inflammation. We investigated pentraxin 3 levels in preeclampsia and intrauterine growth restriction, pregnancy conditions related to altered placentation. Study design:We cross-sectionally studied nonpregnant women (n = 20); normal pregnancies in the first (n = 8), second (n = 10), and third (n = 26) trimester of pregnancy; 20 pregnancies complicated by preeclampsia; and 16 pregnancies complicated by intrauterine growth restriction. Maternal plasma samples were analyzed and pentraxin 3 determined by enzyme-linked immunosorbent assay. Pattern and site of placental expression of pentraxin 3 were studied by immunohistochemistry. Results: In normal pregnancies pentraxin 3 concentrations were significantly higher than nonpregnan twomen and did not change among the 3 trimesters. Significantly higher levels of pentraxin 3 were found in preeclampsia (median values 13.8 versus 2.2 ng/mL;P < .001), compared with normal pregnancies. Intrauterine growth restriction pregnancies showed intermediate levels between normal and preeclamptic patients, but this difference was not significant, compared with normal pregnancies (median values 3.9 versus 2.2 ng/mL). No significant difference of pentraxin 3 levels was found between mild and severe preeclampsia. Conclusion: Elevated maternal plasma levels of pentraxin 3 in preeclamptic versus normal pregnancies could represent a marker of altered endothelial function, typical of preeclampsia. Objective: The prototypic long pentraxin 3 is a new candidate marker for inflammatory conditions reflecting the involvement of the vascular bed. Endothelial dysfunction is a prominent feature of preeclampsia as a result of excessive maternal systemic inflammation. We investigated pentraxin 3 levels in preeclampsia and intrauterine Study of: pregnancy conditions related to altered placentation. Study design: We cross-sectionally studied nonpregnant women (n = 20); normal pregnancies in the first (n = 8), second (n = 10), and third ) 20 pregnancies complicated by preeclampsia; and 16 pregnancies complicated by intrauterine growth restriction. Maternal plasma samples were analyzed and pentraxin 3 determined by enzyme-linked immunosorbent assay. Pattern and site of placental expression of pentraxin 3 were studied by immunohistochemistry. Results: In normal pregnancies pentraxin 3 concentrations were significantly higher than nonpregnan twom Significantly higher levels of pentraxin 3 were found in preeclampsia (median values ​​13.8 versus 2.2 ng / mL; P <.001), compared with normal pregnancies. Intrauterine growth restriction pregnancies showed intermediate levels between normal and preeclamptic patients, but this difference was not significant, compared with normal pregnancies (median values ​​3.9 versus 2.2 ng / mL). No significant difference of pentraxin 3 levels was found between mild and severe preeclampsia. Conclusion: Elevated maternal plasma levels of pentraxin 3 in preeclamptic versus normal pregnancies could represent a marker of altered endothelial function, typical of preeclampsia.