ASH ISTH 2026 guidelines for Anticoagulant Prophylaxis of Pediatric Patients at Risk of Venous Thromboembolism

BACKGROUND: Venous thromboembolism (VTE) is a significant cause of morbidity in children, particularly among hospitalized patients and those with chronic medical conditions. There is a lack of consensus on anticoagulant prophylaxis strategies. OBJECTIVE: These evidence-based guidelines from the American Society of Hematology (ASH) and the International Society on Thrombosis and Haemostasis (ISTH) are intended to support patients and health care professionals in decisions about anticoagulant prophylaxis for pediatric VTE prevention. METHODS: ASH formed a multidisciplinary guideline panel that included 1 patient representative. The University of Kansas Health System supported the guideline development process, including systematic evidence reviews up to April 2025. Clinical questions and outcomes were prioritized according to their importance for clinicians and patients. The panel used the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach to assess certainty in the evidence and make recommendations. RESULTS: The panel agreed on 12 recommendations. For pediatric patients with solid cancer, who have experienced trauma, or who are critically ill, the panel issued conditional recommendations suggesting no anticoagulant prophylaxis. For pediatric patients with antiphospholipid antibody syndrome, or those on long-term total parenteral nutrition, the panel issued conditional recommendations suggesting the use of anticoagulant prophylaxis. Other pediatric subgroups addressed included patients with acute lymphoblastic leukemia or lymphoma, surgical and hospitalized patients, and those with a central venous access device. CONCLUSIONS: High-quality data on anticoagulant prophylaxis for pediatric VTE prevention are scarce. Key research priorities include the development and validation of subgroups-specific VTE risk assessment models, and evaluation of the safety and efficacy of risk-stratified anticoagulant prophylaxis strategies across different pediatric subgroups.