Establishment And Application Of D-dimer Reference Intervals For Chinese Healthy Pregnant And Postpartum Women

Objectives:1. To study D-dimer changes and evaluate some pregnancy-related factors that may influence D-dimer levels.2. To establish D-dimer reference intervals for Chinese healthy pregnant and postpartum women.3. To evaluate the application value of the new reference intervals.Methods:Plasma samples were collected from 669 pregnant,947 postpartum and 80 non-pregnant Chinese women. All samples were tested for D-dimer levels with immunoturbidimetry, and the reference intervals were established based on them. In order to validate the new reference intervals, plasma D-dimer levels were assayed from 8 patients, who were complicated with venous thrombosis(VTE) or disseminated inrvascular coagulation(DIC).Results:1. Plasma D-dimer levels were higher in pregnant and postpartum women compared with non-pregnant women, and the conventional diagnostic threshold for thromboembolism is not suitable for the pregnant and postpartum women; D-dimer level increased progressively during the pregnancy and peaked at the first postpartum day, then it began to decrease steadily at the second postpartum day and reached non-pregnant levels at the 42nd postpartum day; Within the inclusion and exclusion criterias,maternal age,delivery weeks,birthweight and indications for the cesarean sections did not seem to modify D-dimer levels significantly (P>0.05)2. The 95% reference intervals (one-tailed):<13weeks:<0.64mg/L; 14-20weeks:≤1.54mg/L;21-27weeks:<2.60mg/L;28-34weeks:<3.01mg/L;≥35weeks:<3 .19mg/L;the first postpartum day(vaginal delivery):<7.83mg/L;the first postpartum day(cesarean sections):<10.78mg/L;the second postpartum day(vaginal delivery):<3.29mg/L;the second postpartum day(cesarean sections):≤3.80mg/L.3. A positive result could be observed from 8 patients when evaluating their D-dimer levels with the new reference intervals.Conclusions:Trimester specific reference intervals for D-dimer were established in this study, and they proved useful as an aid in the prevention of VTE or DIC during pregnancy and postpartum.