Dynamic Computed Tomography Findings as Indicators of Uterine Artery Embolization in Postpartum Hemorrhage.

Importance: Postpartum hemorrhage (PPH) remains the leading cause of maternal mortality globally. Although traditional management relies on blood loss quantification, identifying cases resistant to conventional treatment remains challenging, potentially delaying crucial interventions. Objective: To determine the prevalence and clinical implications of PPH that is resistant to treatment showing arterial contrast extravasation on dynamic computed tomography (CT) (PRACE) and its association with intervention requirements. Design, Setting, and Participants: A multicenter retrospective case-control study of PPH cases was conducted at 43 tertiary facilities across Japan, including 30 university hospitals, between January and December 2021. The study included patients with PPH who were either transported to the centers or who delivered there. Data analysis was performed from September 2023 to November 2024. Exposure: A diagnosis of PPH, defined as blood loss exceeding 2000 mL or requiring more than 10 units of red blood cell transfusion. Main Outcomes and Measures: The primary outcome was the prevalence of PRACE and its association with uterine artery embolization (UAE) requirement. Secondary outcomes included risk factors for severe coagulopathy (fibrinogen <150 mg/dL). Odds ratios (ORs) were estimated using multivariable logistic regression to evaluate the association between types of PPH (atonic uterus, tissue, and PRACE) and PPH severity. Results: Among 352 patients (median [IQR] age, 33.0 [30.0-37.0] years; 211 [60.0%] primiparous), 205 (58.2%) underwent CT scans, with PRACE detected in 58 (32.2%) of evaluable cases. Patients with PRACE had significantly higher total blood loss (median [IQR], 3455 [2000-5070] mL vs 2500 [1500-2650] mL) and greater UAE requirement (50 of 58 patients [86.2%] vs 35 of 122 patients [28.7%]) compared with patients without PRACE. PRACE was the primary factor associated with the need for UAE (OR, 27.74; 95% CI, 10.52-83.14). Conclusions and Relevance: In this retrospective case-control study of patients with severe PPH undergoing dynamic CT, PRACE represented a distinct and common pathology in severe PPH and was associated with the need for interventional procedures. These findings suggest that dynamic CT imaging should be considered as an essential diagnostic tool in managing treatment-resistant PPH cases.