Preeclampsia is associated with a reduced response to activated protein C

OBJECTIVE: Resistance to activated protein C is an inherited mutation of the coagulation factor V gene, a major factor predisposing to thromboembolic events. The purpose of this study was to investigate the occurrence of heterozygote and homozygote activated protein C resistance in women with preeclampsia. STUDY DESIGN: Activated protein C resistance and protein C and antithrombin III levels were determined in women (n = 50) with a history of preeclampsia and in controls (50 women with a previous normal pregnancy). The mutation of the factor V gene was analyzed. RESULTS: Activated protein C resistance was found in 22% of women with previous preeclampsia compared with 10% among controls. Two women in the previous preeclampsia group had a homozygote mutation of factor V; the others were heterozygous. There was a significant difference in the activated protein C ratio between women with previous preeclampsia and the control group, 2.6 +/- 0.4 versus 3.1 +/- 0.5 (p = 0.04). None of the women had protein C or antithrombin III deficiency. CONCLUSION: The results indicate that activated protein C resistance may be a contributory factor in the pathogenesis of preeclampsia.