D-Dimer Plasma Levels in Each Trimester of Diabetic Pregnant Women, A Case Control Study

Background and objectives: Pregnancy increases D-dimer levels, making it a non-specific test for venous thromboembolism. This study compared D-dimer levels by trimester in healthy and diabetic pregnant women. Methods: A case-controlled study was conducted from May 2022 to August 2023 at Gestational Diabetes Clinic/Maternity Teaching Hospital, Erbil City, Kurdistan Region, Iraq to compare D-dimer levels between two groups: 360 pregnant women diagnosed with diabetes (cases) and 360 normoglycemic pregnant women (controls). Blood samples were obtained once from each participant during a prenatal visit. Samples were collected from a vein and analyzed using a latex-based immunofluorescence assay on a Biozek DCR1000 machine to measure D-dimer concentration. Results: D-dimer levels steadily increased throughout pregnancy in both groups, peaking in the third trimester. Notably, pregnant women with diabetes consistently had significantly higher D-dimer levels compared to controls across all trimesters (p < 0.001). Within the diabetic group, women with type 1 diabetes displayed the highest mean D-dimer concentration (1887.3 ng/ml), significantly higher than both type 2 diabetes (1518.0 ng/ml; p = 0.036) and gestational diabetes (1155.8 ng/ml; p = 0.004). Conclusions: This study highlights a substantial rise in D-dimer levels throughout pregnancy, even in healthy women. Importantly, pregnant women with diabetes have considerably higher D-dimer levels compared to controls, with the highest observed in type 1 diabetes. These findings emphasize the need to consider diabetes when interpreting D-dimer levels for venous thromboembolism diagnosis in pregnancy.