BACKGROUND: Increased maternal plasma levels of proinflammatory cytokines as well as the anti-angiogenic agents soluble fms-like tyrosine kinase 1 (sFlt-1) and endoglin (sEng) are associated with promoting vascular dysfunction leading to the maternal syndrome of preeclampsia. OBJECTIVE AND METHOD: Nulliparous women complicated with preeclampsia (n = 29) and their corresponding controls (n = 29) delivering at the Enrique C. Sotomayor Obstetrics and Gynecology Hospital, Guayaquil-Ecuador were requested to participate in a study evaluating plasma levels of soluble anti-angiogenic factors (sFlt-1 and sEng) and pro-inflammatory cytokines: interleukin 6 (IL-6), interleukin 8 (IL-8), granulocyte colony stimulating factor (G-CSF), and tumor necrosis factor-alpha (TNF-alpha). Maternal and neonatal data were also assessed and compared among the study groups. RESULTS: No significant differences in either maternal baseline or delivery characteristics were observed among the study groups. Compared with controls, preeclamptic women exhibited higher plasma levels of sFlt-1 (19.0 +/- 15.1 vs. 12 +/- 8.3 ng/mL) and of sEng (20.4 +/- 9.9 vs.15.9 +/- 9.4 ng/mL); respectively, p < 0.05. Women with severe disease displayed higher sFlt-1 and sEng levels when compared with mild ones (34.5 +/- 11.6 vs. 9.5 +/- 1.6 ng/mL, and 29.5 +/- 9.0 vs. 14.8. +/- 5.2 ng/mL, respectively; p < 0.001). In contrast, women with preeclampsia exhibited significant lower IL-8 and G-CSF levels compared with controls. No differences existed between either group in IL-6 levels or TNF-alpha. CONCLUSION: Consistent with previous reports, increased sFlt-1 and Eng levels in maternal plasma is consistent with vascular dysfunction found in gestations complicated with preeclampsia.