Viscoelastic testing in postpartum obstetric hemorrhage: a scoping review commissioned by the Patient-Centered Outcomes Research Institute (PCORI)

Abstract

Background: Hemorrhage is a leading cause of maternal mortality worldwide. Most deaths due to postpartum hemorrhage are considered preventable. Viscoelastic testing rapidly measures mechanical properties of coagulation in real time, providing insights into blood clot formation, stability and dissolution. The objective of this scoping review was to identify and map use of viscoelastic testing, including thromboelastography and rotational thromboelastometry, in obstetrics for postpartum hemorrhage. Methods: As part of a larger landscape review, we followed a detailed workplan outlining methods a priori (https://osf.io/mzr6p). Literature searches in July 2025 included 14 databases searched from inception. Reporting followed PRISMA-ScR. Results: The scoping review shows a growing evidence base of viscoelastic testing for postpartum hemorrhage. We identified 106 research studies reported in 156 publications, but few published randomized controlled trials. Many observational studies, predominantly published in Europe, document experiences with viscoelastic testing in practice, although many are still only published in abbreviated form (e.g. conference abstracts). Barriers to adoption include cost, provider knowledge and acceptance, training, and research challenges. Future research needs to assess the effect of viscoelastic testing protocols on maternal morbidity and organizational impact by using methods suitable for rare and largely unpredictable events. We outline specific recommendations for practice and research. Conclusions: Viscoelastic testing offers point-of-care monitoring of coagulation, enabling real-time decision support to guide transfusion therapy. Protocols may reduce transfusion volume, postoperative bleeding, and prevent overtreatment, but more clinical guidance and rigorous multicenter studies to determine the impact of protocols for use in postpartum hemorrhage care empirically are needed.