Clinical Characteristics and Outcomes of Pregnancy-Associated Venous Thromboembolism　- Report From the Japanese...

Pregnant women are at high risk of venous thromboembolism (VTE), which is one of the important causes of maternal death.

Using a Japanese nationwide hospital administrative database, we identified 410 pregnant women who were admitted to hospital with VTE between April 2008 and September 2023. We evaluated clinical characteristics and outcomes. Of the 410 women, 110 (26.8%) developed pulmonary embolism (PE). The median week of pregnancy at the time of VTE onset was 31 weeks. The incidence of VTE exhibited a bimodal distribution: 126 (30.7%) women developed VTE in the first trimester (before 14 weeks gestation) and 236 (57.6%) developed VTE in the third trimester (after 28 weeks gestation). PE was more common in the later stages of pregnancy. Regarding anticoagulation therapy, 374 (91.2%) women received unfractionated heparin and 18 (4.4%) received low-molecular-weight heparin. During the 6-month follow-up period, 17 (4.1%) women experienced VTE recurrence and 3 (0.7%) developed bleeding events, including intracranial hemorrhage and gastrointestinal bleeding. During hospitalization, 4 (1.0%) women died, 3 of whom had a history of surgical procedures, including cesarean section and hysterectomy.

This large nationwide database revealed important clinical features and outcomes of pregnancy-associated VTE, highlighting its bimodal incidence and the need for early vigilance, benefiting cardiologists and obstetricians.