Effects of red blood cells on the coagulation of blood in normal and preeclamptic pregnancies

OBJECTIVE: The objective of this study was to determine the cellular effect s of whole blood, especially of red blood cells, on the hypercoagulability of blood from patients with preeclampsia. STUDY DESIGN: The time elapsed between mixing and the onset of coagulation was measured by means of a highly sensitive rheometer for whole blood, plat elet-rich plasma (in which red blood cells had been removed from whole bloo d), and platelet-free plasma from 3 groups of subjects: 25 nonpregnant wome n, 25 women with normal pregnancies, and 10 patients with preeclampsia. RESULTS: Time to coagulation for whole blood from patients with preeclampsi a was significantly shorter than that for whole blood from women with norma l pregnancies. However, there was no significant difference in time to coag ulation for platelet-rich plasma between women with preeclampsia and those with normal pregnancies. CONCLUSION: Hypercoagulability of blood in preeclampsia appears to be stron gly related to red blood cell alterations.