Coagulation activation markers do not correlate with the clinical risk of thrombosis in pregnant women

OBJECTIVE: Because coagulation activation markers have been shown to indica te an increased risk of thrombosis, we tested whether thrombin-antithrombin III complexes and D-dimers correlated with the risk assessment in pregnant women on the basis of clinical data. STUDY DESIGN: We divided a group of 261 pregnant women (305 pregnancies) in to low- and high-risk groups according to the personal and family histories of thrombosis and the presence of a hereditary or an acquired thrombophili a. Women with a thrombotic event in the current pregnancy formed a separate group. All pregnancies with or without heparin therapy were closely monito red with thrombin-antithrombin III and D-dimer values for the entire course of the pregnancy. Retrospectively, the data were then correlated with the different groups and subgroups. RESULTS: The course of the mean thrombin-antithrombin III values of all 305 pregnancies was close to or slightly above the upper cutoff line, whereas the D-dimer values were well within the normal range. Independent of hepari n, there was no difference in the course of the thrombin-antithrombin III a nd D-dimer values between the low- and high-risk groups. Only women with on going thrombosis during pregnancy had significantly higher thrombin-antithr ombin III and D-dimer values with or without heparin therapy. Among those i ndividuals with elevated thrombin-antithrombin III or D-dimer values, there were no specific, recognizable patients who had elevated markers more ofte n than others. CONCLUSIONS: Thrombin-antithrombin III and D-dimer values do not correlate with a risk stratification assessed by clinical criteria. There are many wo men at low clinical risk who have elevated markers, and there are many wome n at very high clinical risk who have normal markers. Thus thromboprophylax is would often be used inadequately if the indication were based on coagula tion markers.