The Global, Regional, and National Burden of Postpartum Hemorrhage, 1990-2040: A Systematic Analysis Based on the Global Burden of Disease Study.

Background: Postpartum hemorrhage (PPH) remains one of the leading global causes of maternal morbidity and mortality. To date, however, comprehensive long-term epidemiological trends and standardized future projections of PPH burden stratified by socioeconomic level have not been sufficiently characterized. This study aimed to systematically analyze the global, regional, and socioeconomic-stratified burden of PPH from 1990 to 2021, and forecast epidemiological trends through 2040, to provide evidence for targeted global maternal health interventions. Methods: Based on publicly available aggregated data from the 2021 Global Burden of Disease Study (GBD 2021), this secondary ecological analysis estimated the age-standardized incidence rate (ASIR), age-standardized prevalence rate (ASPR), age-standardized mortality rate (ASMR), and age-standardized disability-adjusted life-year rate (ASDR) across 204 countries and territories. We calculated temporal trend inflection points and annual percentage changes (APC) using Joinpoint regression, and applied optimized autoregressive integrated moving average (ARIMA) models to project future trajectories of PPH burden through 2040. The slope index of inequality (SII) and concentration index (CI) were used to quantify absolute and relative socioeconomic disparities in PPH burden. Results: Globally, the age-standardized incidence rate (ASIR) of PPH decreased steadily from 495.93 per 100,000 population in 1990 to 358.57 per 100,000 population in 2021, with an estimated annual percentage change (EAPC) of -0.83%. Stratified by socio-demographic index (SDI), low-SDI regions had the highest PPH burden in 2021 (ASIR: 740.01 per 100,000 population), while high-SDI regions maintained the lowest burden (ASIR: 192.76 per 100,000 population). Exploratory ARIMA projections indicate that if current trends continue, global PPH morbidity measured by ASIR and age-standardized prevalence rate (ASPR) will likely show an upward trend by 2040. This increasing trend is mainly driven by epidemiological transitions in middle-SDI regions, while global PPH mortality is projected to continue declining. However, these projections carry considerable uncertainty, especially for longer forecasting horizons, and should be interpreted as exploratory "what-if" scenarios rather than deterministic predictions. Over the past three decades, absolute socioeconomic inequalities in PPH burden have narrowed, while relative disparities increased slightly, with women aged 25-29 years identified as the highest-risk population globally. Conclusion: Over the past three decades, the global burden of postpartum hemorrhage (PPH) has decreased notably. However, distinct socioeconomic and regional disparities persist: low-SDI regions still face severe mortality risks linked to PPH, while middle-SDI regions are grappling with new morbidity challenges driven by population aging and changing obstetric risk profiles. To address global maternal health inequities, stratified, context-adaptive public health strategies tailored to each region's unique socioeconomic and epidemiological characteristics are needed. Given the inherent uncertainties of the ARIMA modeling approach, all forecast results should be interpreted with caution.