Viscoelastic Hemostatic Assays in Postpartum Hemorrhage and Pregnancy.

Viscoelastic hemostatic assays (VHAs), such as thromboelastography, rotational thromboelastometry, and Quantra, are increasingly used to guide postpartum hemorrhage (PPH) resuscitation. We review device principles, reference ranges, transfusion thresholds, and algorithmic integration. Pregnancy-specific VHA thresholds identify hypofibrinogenemia requiring replacement with cryoprecipitate or fibrinogen concentrate. Algorithms with VHA-guided bundles may reduce massive PPH morbidity and allogeneic transfusion requirements. VHA platelet indices correlate only at low counts; anticoagulants and temperature/pH can confound results. VHA-enabled, threshold-based algorithms expedite targeted therapy in PPH, reduce plasma exposure, and complement standard laboratories and clinical judgment.