Diagnostic Value of D-Dimer Concentration for Pregnancy-related Venous Thromboembolism: A Retrospective Study

Background: Venous thromboembolism includes deep vein thrombosis and pulmonary embolism. Pulmonary embolism is the leading cause of maternal death and results in adverse pregnancy outcomes. Plasma D-dimer detection has high diagnostic value in nonpregnant people. We retrospectively analyzed factors affecting the plasma D-dimer concentration to establish a pregnancy-specific reference interval of plasma D-dimer. Our goal was to explore the diagnostic value of D-dimer for pregnancy-related venous thromboembolism. Methods The general condition, complications, and pregnancy outcomes of 2,012 women hospitalized for delivery from 1 January 2020 to 31 December 2020 in Beijing Friendship Hospital Affiliated to Capital Medical University were collected. The D-dimer concentration was collected in the first, second, and third trimesters and within 48 hours after delivery. The trend of the D-dimer concentration and influencing factors were statistically analyzed. Pregnancy-specific D-dimer reference intervals were established. Results The plasma D-dimer concentration gradually increased as pregnancy progressed. The median (2.5th–97.5th percentiles) in the first, second, and third trimesters and within 48 hours postpartum were 0.60 (0.30–1.50), 1.15 (0.31–5.38), 1.70 (0.80–4.89), and 4.65 (1.12–40.78) µg/mL, respectively. In the first trimester, multiparity and in vitro fertilization and embryo transfer (IVF-ET) were associated with significantly higher D-dimer concentrations. In the third trimester, twin pregnancy and IVF-ET were associated with significantly higher D-dimer concentrations. Cesarean section was an independent risk factor within 48 hours postpartum. After removal of interfering factors, reference intervals of the D-dimer levels in the first trimesters were established, 95%CI (unilateral) ~ 1.00µg/mL. The optimal cutoff value for VTE in the third trimester predicted by the ROC curve was 3.40 µg/mL. Conclusions The plasma D-dimer level gradually increased as pregnancy progressed. Risk factors for abnormally high D-dimer levels included multiparity and IVF-ET in the first trimester, twin pregnancy and IVF-ET in the third trimester, and cesarean section in puerperium. Upper limit value of the D-dimer levels in the first and third trimesters were suggested with 1.00 µg/mL and 3.40 µg/mL.