Obstetric venous thromboembolism: Evaluation of prophylactic approach based on risk scores, D‐dimer levels, and ultrasonography findings in a tertiary hospital in Japan

Aim Pulmonary embolism remains a leading cause of maternal mortality in developed countries despite developments in venous thromboembolism prophylaxis strategies. This study aimed to evaluate the effectiveness of our approach involving risk‐scoring, D‐dimer level assessment, and ultrasonography for obstetric venous thromboembolism. Methods This retrospective cohort study included women who delivered at 22–41 weeks of gestation in The University of Tsukuba Hospital, Japan between January and December 2020. Venous thromboembolism risk (determined according to Japanese guidelines) and D‐dimer levels were evaluated within 20 weeks of gestation, 30–34 weeks of gestation, and during the pre‐delivery period (36 weeks of gestation or any time before preterm delivery). Compression and color Doppler ultrasonography for lower extremity deep vein thrombosis were performed if D‐dimer levels were ≥3.2 μg/mL (for those undergoing cesarean delivery, 1.0 μg/mL). Results Of 1026 women, 6 women had deep vein thrombosis during pregnancy and 1 during the puerperium period. Pulmonary embolism was not observed. The D‐dimer screening result was positive for 8 women (2%) within 20 weeks of gestation (deep vein thrombosis was confirmed in 3 of them), 87 women (10%) (no deep vein thrombosis) at 30–34 weeks of gestation, and 367 women (36%) during the pre‐delivery period (asymptomatic deep vein thrombosis in one). Based on the Japanese guidelines, 1%, 11%, 33%, and 55% of women had high, intermediate, low, and no postpartum risk factors, respectively. Conclusions Our approach appears useful for antenatal venous thromboembolism screening in the first trimester. For postpartum prophylaxis, more cost‐effective strategies are needed.