Key takeaways:
- Objective blood loss assessment methods identify postpartum hemorrhage at rates more than 3 times higher than subjective visual estimation after vaginal birth.
- Severe postpartum hemorrhage is also more frequently detected with objective measurement, particularly following cesarean delivery.
- The meta-analysis included 81 studies with predominantly high-quality evidence, strengthening confidence in the findings.
- Mean blood loss was substantially higher after cesarean birth than vaginal birth, underscoring the need for accurate measurement across delivery modes.
- Improved detection of postpartum hemorrhage through objective methods could inform better resource allocation, clinical management, and maternal health outcomes.
Research published in The Lancet Obstetrics, Gynecology, & Women’s Health has highlighted increased rates of postpartum hemorrhage when using objective blood loss assessment methods, indicating underestimation from subjective methods.1
Postpartum hemorrhage, defined as blood loss of 500 mL or more within 24 hours after birth, is commonly measured using subjective visual estimation of blood loss. However, concerns have arisen about this method underestimate the true burden of the condition.
“Objective blood loss assessment methods to diagnose postpartum hemorrhage have been shown to have high levels of accuracy; as a result, studies using these methods are more likely to estimate the true prevalence of postpartum hemorrhage,” wrote investigators.
Blood loss assessment
The systematic review and meta-analysis were conducted to compare subjective and objective measurements of postpartum hemorrhage. Articles on postpartum hemorrhage were obtained from the Web of Science, PubMed, Google Scholar, Embase, Cochrane Database, and ISRCTN registry databases.
Cross-sectional studies, randomized controlled trials, and large cluster randomized trials were eligible. These articles underwent title and abstract screening by 5 independent authors, followed by full-text screening. These authors also performed data extraction.
Relevant data included study design, publication details, data linked to postpartum hemorrhage or severe postpartum hemorrhage, country and continent of participants, blood loss assessment method, amount of objectively measured blood loss, data collection period, data and population source, age range of participants, mode of births, number of births, and number of postpartum hemorrhages.
Subjective assessment was defined as the visual estimation of blood loss, while objective assessment was defined as the use of volumetric or gravimetric approaches. Pooled rates of postpartum hemorrhage and severe postpartum hemorrhage were reported as the primary outcomes.
Higher detection rates with objective measurement
There were 81 studies included in the final analysis, 65 of which assessed postpartum and severe postpartum rates, and 20 measured postpartum blood loss. Both assessments were performed in 4 of the 81 studies. High quality of evidence was reported in 96% of studies vs moderate quality in 4%.
In vaginal birth cases, a pooled prevalence of 12.6% was reported for objectively measured postpartum hemorrhage. In comparison, the rate for subjectively measured postpartum hemorrhage was 3.9%, highlighting an over 3-fold increase in detection through objective measurements.
For severe postpartum hemorrhage, rates identified by objective and subjective measurement were 3.3% and 2.3%, respectively. Additionally, objectively diagnosed severe postpartum hemorrhage had a pooled prevalence of 8.5% after cesarean birth, vs 3.7% for subjective diagnosis.
Blood Loss differences by mode of delivery
After vaginal birth, a mean blood loss of 352.99 mL was reported, vs 875.60 mL after cesarean birth. Overall, the data highlighted improved accuracy of blood loss assessment from objective methods vs subjective methods.
“Knowledge of the true prevalence can allow policy makers to provide the required services and resources to prevent, diagnose, and treat postpartum hemorrhage,” wrote investigators.
Clinical and public health implications
The importance of managing postpartum hemorrhage cases has been highlighted by Kameelah Phillips, MD, founder of Calla Women’s Health, in an interview with Contemporary OB/GYN.2Phillips noted that postpartum hemorrhage is a leading cause of maternal morbidity and mortality, with difficulty quantifying blood loss being a significant challenge in these cases.
Women residing in maternity care deserts have a greater risk, as obstetric care is sparse or unavailable in these regions. This increases the risks of preterm birth, postpartum hemorrhage, and other severe maternal health issues among this population of approximately 2 million US women.
“Health care professionals [should] have open communication with their patients to formulate the right plan to optimize their pregnancy and birth experience, and even the postpartum experience,” said Phillips.
References
- Yunas I, Asiful Islam M, Price MJ, et al. Prevalence of postpartum hemorrhage: a systematic review and meta-analysis. The Lancet Obstetrics, Gynecology, & Women’s Health. 2025. doi:10.1016/S3050-5038(25)00123-2
- Krewson C. Understanding and managing postpartum hemorrhage: Insights from Kameelah Phillips, MD. Contemporary OB/GYN.November 8, 2024. Accessed December 15, 2025. https://www.contemporaryobgyn.net/view/understanding-and-managing-postpartum-hemorrhage-insights-from-kameelah-phillips-md
