Quantification of blood loss in obstetric haemorrhage: implications on intervention and transfusion

Postpartum haemorrhage accounts for 27% of all maternal deaths. Incorrect quantification of blood loss can lead to unnecessary interventions, such as the transfusion of blood products, which is not without risk. During pregnancy, cardiovascular changes may explain how blood loss can occur rapidly, with pregnant women tolerating large volumes of blood loss before a change in clinical signs is seen. Several methods are used to quantify blood loss, such as visual estimation, volumetric, gravimetric, colorimetric and photometric. The Obstetric Bleeding Strategy for Wales (OBS Cymru) project, which standardised management of obstetric haemorrhage in Wales using a four‐stage approach, showed a statistically significant improvement in outcomes. Different definitions of postpartum haemorrhage make it difficult to compare available evidence. Further studies are required combining the use of point‐of‐care tests and quantitative techniques to help improve morbidity and mortality associated with obstetric haemorrhage.