Point-of-care visco-elastic testing for postpartum haemorrhage: A narrative review.

Postpartum haemorrhage (PPH) remains a leading cause of maternal morbidity and mortality worldwide. While coagulation disorders are seldom the primary cause of PPH and are rare early in PPH, the incidence of coagulation abnormalities increases when blood loss escalates. Acute obstetric coagulopathy (AOC), with an incidence of one in 1000 deliveries, has emerged as a distinct coagulopathy in PPH, highlighting the need for timely coagulation testing and intervention. This narrative review examines the current evidence on the use of visco-elastic haemostatic assays (VHAs) to guide treatment in PPH, and further explores the prophylactic and therapeutic roles of fibrinogen and tranexamic acid (TXA). VHAs have shown potential in PPH management, with large prospective and retrospective cohort studies demonstrating reductions in transfusions and transfusion-related complications. However, these findings have not been consistently replicated, possibly due to variations in study design and statistical power. This review explores the benefits and limitations of VHAs in the context of PPH management. Until large, well designed studies suggest otherwise, women with PPH might benefit from access to VHAs, given their potential to improve clinical outcomes in large cohorts without evidence of associated harm. Fibrinogen replacement is essential in PPH management. VHAs have been shown to be as effective as the Clauss fibrinogen assay in guiding fibrinogen substitution during PPH. Recent updates to ROTEM Sigma cartridges have led to new FIBTEM A5 thresholds, with the Obstetric Bleeding Strategy (OBS) group of Wales proposing a FIBTEM A5 of 8 mm or less as the new trigger for fibrinogen replacement in PPH. Fibrinogen concentrate offers advantages over cryoprecipitate and may be preferred when both are available. Effective fibrinogen substitution not only corrects VHA results but also helps to control bleeding. TXA is a cornerstone in the treatment of PPH and should be administered promptly at a dose of 1 g as soon as PPH is diagnosed, regardless of VHA results, and always within three hours of onset. A second dose may be given if bleeding persists or recurs. However, high-quality randomised trials have consistently shown no benefit from prophylactic TXA in low-risk caesarean section or in vaginal births across all risk groups. Data on the prophylactic use of TXA in high-risk caesarean section are limited and its use in these cases should be based on clinical judgement and individual risk assessment.