Since July 2022, obstetrical disseminated intravascular coagulation (DIC) in Japan has been diagnosed based on the new criteria (tentative version), which assesses the main underlying disease, fibrinogen level, and fibrin/fibrinogen degradation products or D-dimer level. In June 2024, the tentative version underwent minor revision and the final version was released. The previous Japanese criteria assessed underlying disease, clinical symptoms, and various laboratory findings. This study aimed to prove the effectiveness, reliability, and validity of the new criteria (final version). We analyzed 212 women with singleton pregnancies who delivered after 22 gestational weeks and experienced blood loss ≥ 1000 mL during vaginal delivery or ≥ 2000 mL during cesarean section. Those with missing laboratory findings before receiving blood transfusion at delivery were excluded. In the obstetrical DIC group, the frequency of fibrinogen levels < 150 mg/dL was significantly higher than in the control group (90% vs. 5%, p < 0.0001), as was the frequency of scores ≥ 8 according to the previous Japanese criteria (100% vs. 10%, p < 0.0001). Cronbach alpha was 0.757 and Spearman\'s rank-order correlation was 0.558 between the new and previous criteria. In conclusion, we proved the effectiveness, reliability, and validity of the Japanese new criteria (final version) to diagnose obstetrical DIC.

The new Japanese diagnostic criteria for obstetrical disseminated intravascular coagulation (DIC) (tentative version) were released in June 2022. We aimed to demonstrate the differences in characteristics between women with DIC diagnosed using the new Japanese criteria and those diagnosed using the pregnancy-specific modified International Society on Thrombosis and Hemostasis DIC score, also known as the pregnancy-specific modified ISTH DIC score, which was released in 2014. In this retrospective cohort study, all participants were retrospectively diagnosed based on both criteria. Six women were diagnosed with obstetrical DIC based on both criteria (Group A). Of the 43 women diagnosed with obstetrical DIC based on the worldwide criteria, 36 were diagnosed with non-obstetrical DIC based on the new Japanese criteria (Group B). Group A had significantly lower fibrinogen levels and significantly higher prothrombin time differences and scores of underlying diseases (particularly postpartum hemorrhage with coagulopathy) and laboratory findings than Group B. Additionally, Group A had significantly higher rates of platelet concentrate (PC) transfusion therapy for obstetrical DIC and more transfusions of fresh frozen plasma and/or cryoprecipitate, red blood cells and PC than Group B. Thus, the new Japanese criteria detected more severe cases of obstetrical DIC compared with the worldwide criteria.