The clinical significance of D-dimer concentrations in patients with gestational hypertensive disorders according to the severity

Objective Pregnancy is a major risk factor of thromboembolism, and the patients with preeclampsia (PE) are known to have higher risk of thromboembolic complications than normal pregnant women. D-dimer is a well-established laboratory marker for the screening of venous thromboembolism (VTE), but the concentrations of d-dimer tend to increase physiologically in pregnant women throughout the gestational age. We performed this study to evaluate the clinical significance of d-dimer concentrations in patients with gestational hypertensive disorders (GHD) according to the severity. Methods Retrospective cohort study was performed in one institution. Singleton pregnant women with GHD were enrolled, and their antepartum concentrations of d-dimer were measured as a part of routine evaluation for patients suspected with PE. Patients with multiple gestations, rheumatic diseases, autoimmune diseases, or suspected VTE were excluded. A categorization of severity about PE was based on the general criteria. Results In 73.3% of study population, their d-dimer concentrations exceeded the normal range (>0.55 mg/L). A significantly greater proportion of pregnant women had excessive concentrations of d-dimer in the severe GHD than in the non-severe GHD (89.8% vs. 53.7%; P<0.01). Patients with severe GHD had significantly higher median concentrations of d-dimer than those with non-severe GHD (median [range], 2.00 mg/L [0.11 to 7.49] vs. 0.71 mg/L [0.09 to 5.39]; P<0.01) although their earlier gestational ages of sampling. Conclusion Maternal concentrations of d-dimer were significantly elevated in patients with severe features than those without severe features among those with GHD. Some pregnant women with GHD can have markedly elevated concentrations of d-dimer without any evidence of current VTE.