The global, regional, and national burdens of maternal sepsis and other maternal infections and trends from 1990 to 2021 and future trend predictions: results from the Global Burden of Disease study 2021 | BMC Pregnancy and Childbirth

Trends in MSML incidence, death and dalys from 1990 to 2021

From 1990 to 2021, the global burden of MSMI underwent significant changes. Table 1 offers a detailed comparison of incidence, ASR, and relative changes by SDI levels and GBD regions over this period, including EAPC values. Globally, MSMI cases decreased from 22.45 million to 19.05 million, with the ASR dropping from 764.03 to 494.19 per 100,000 people, representing a reduction of 35.32%. The EAPC in ASR was − 1.18, indicating an overall downward trend.

Performance varied significantly across SDI groups. Most SDI categories showed declines, with high-middle SDI regions experiencing the largest decrease (-41.24%), while low SDI regions saw a 53.87% increase in cases. The ASR consistently decreased across all SDI groups, with the largest decline in low-middle SDI regions (-48.59%). Despite the overall reduction, significant disparities remain between SDI regions.

Among GBD regions, MSMI cases exhibited both increases and decreases. Western Sub-Saharan Africa had the most notable increase (90.72%), whereas Central Europe and East Asia saw the most significant decreases (-60.53% and − 59.59%). ASR mostly decreased across regions, with South Asia showing the largest decline (-53.82%), while Australasia experienced a slight increase (3.50%). The EAPC results showed that South Asia and North Africa and the Middle East had the greatest decreases, whereas Eastern Europe and Australasia showed a persistent upward trend in ASR.

We used bar charts and line graphs to visualize the analysis. Figure 1A illustrates the trends in MSMI incidence from 1990 to 2021, showing a steady decline in cases from approximately 22 million in 1990 to 12 million in 2021. The ASR similarly decreased from 764 to 494 per 100,000, reflecting the impact of improved healthcare interventions and preventive measures globally. Figure 1B shows MSMI-related deaths, which rose from 20,000 in 1990 to 30,000 in the early 2000s, before declining to 10,000 by 2021. This trend suggests an initial worsening followed by significant improvements in MSMI management. The ASR peaked at 1.0 per 100,000 in the early 2000s, then dropped to 0.5 per 100,000 by 2021, highlighting advancements in care and the effectiveness of interventions. Figure 1C presents the burden of MSMI in DALYs, which increased from 1 million in 1990 to 2 million in the early 2000s before falling back to 1 million in 2021. The ASR halved, decreasing from 60 to 30 per 100,000, indicating significant progress in reducing long-term health impacts and improving quality of life for those affected.

Burden of MSMI based on age

The analysis of MSMI burden by age group from 1990 to 2021 revealed that women aged 20–34 consistently experience high incidence, death, and DALYs, with the highest burden observed in the 20–24 age group. The incidence of MSMI peaked in this age group, with approximately 6 million cases and an ASR exceeding 2,000 per 100,000 (Fig. 2A). Similarly, the number of deaths peaks in the 20–24 age group, with around 4,000 deaths and an ASR exceeding 1.4 per 100,000 (Fig. 2B). The DALYs are also highest in this age group, with approximately 300,000 DALYs and an ASR exceeding 100 per 100,000 (Fig. 2C). The results indicate that targeted interventions for women in these age groups are crucial.

Joinpoint regression analysis of MSMI

The joinpoint regression analysis indicated significant improvements in MSMI incidence, death, and DALYs, particularly after 2000 (Table 2). Specifically, MSMI incidence showed a significant decline over the study period, with an AAPC of -1.40% (95% CI, -1.45 to -1.35). The decline was most pronounced from 1990 to 1994 (APC − 2.50%) and from 2015 to 2021 (APC − 2.07%). Death due to MSMI also demonstrated a notable reduction, with an AAPC of -2.29% (95% CI, -2.50 to -2.08). Following a slight increase from 1995 to 2000 (APC 1.86%), substantial declines were observed, especially from 2007 to 2015 (APC − 5.28%). Similarly, DALYs decreased significantly, with an AAPC of -2.24% (95% CI, -2.44 to -2.04). Although there was a temporary increase from 1995 to 2000 (APC 1.80%), the period from 2007 to 2015 saw the sharpest decline (APC − 5.12%). Overall, the data indicate that despite periods of slower progress and setbacks, the long-term trends in MSMI incidence, death, and DALYs were consistently positive, reflecting improvements in healthcare and intervention measures globally.

Analysis of MSMI attributable to iron deficiency as a risk factor

Figure 3A and B compare the percentages of death and DALYs due to MSMI attributable to iron deficiency across different SDI categories between 1990 and 2021, respectively. Globally, the percentage of death attributable to iron deficiency in MSMI increased slightly from 17.39% in 1990 to 18.04% in 2021. High SDI regions experienced a notable decrease from 19.72 to 16.79%, reflecting effective interventions and improvements in healthcare. Conversely, low and low-middle SDI regions experienced an increase in iron deficiency, highlighting ongoing challenges in addressing iron deficiency. High-middle and middle SDI regions showed relatively stable percentages with only minor increases. For DALYs, the global percentage attributable to iron deficiency rose from 17.37% in 1990 to 17.99% in 2021. The trends across different SDI regions were similar to those observed for deaths: high SDI regions experienced significant reductions, indicating improved quality of life and reduced long-term health impacts due to better iron management. However, low and low-middle SDI regions experienced increases. High-middle and middle SDI regions slightly increased, indicating a persistent issue.

The effect of age, period, and cohort on the incidence, death, and dalys of MSMI

Age effects

After controlling for period and cohort effects, the age effect showed significant variations in the risk of MSMI and related outcomes. Incidence and death peaked in the 20–29 age group, with relative risks (RRs) of up to 9.103 for incidence and 3.460 for death, identifying these age groups as the most vulnerable to MSMI. Risks declined significantly for individuals over 30, with the lowest risks observed in the 50–54 age group.(Table 3).

Period effects

Period effects indicate the impact of healthcare improvements and public health interventions. From 1992 to 2021, the RRs for both incidence and death demonstrated a general downward trend, with significant declines especially after the early 2000s. The incidence RR decreased from 1.241 in 1992–1996 to 0.884 in 2017–2021, reflecting the positive influence of enhanced healthcare services.

Cohort effects

Cohort effects reveal higher risks for older birth cohorts, such as those born between 1938 and 1942, with RRs of 1.063 for incidence and 1.288 for death. In contrast, younger cohorts, particularly those born after 1980, experienced notable risk reductions, with cohorts born between 1998 and 2002 showing RRs of 0.89 for incidence and 0.79 for death, reflecting improvements due to modern healthcare interventions.

Decomposition analysis of the augmented incidence cases

The decomposition analysis assessed the increase in MSMI incidence from 1990 to 2021 by incorporating epidemiological changes, population growth, and aging (Fig. 4). Globally, epidemiological changes contributed the most to the rise in incidence across all SDI quintiles. Population growth was a major driver, especially in low and low-middle SDI regions, while population aging had a notable impact in high and high-middle SDI regions. The largest increases were observed in low and low-middle SDI regions, driven by both population growth and epidemiological changes. In high SDI regions, the contributions from all three factors were more balanced, indicating better control over incidence rates. These findings emphasize the need for targeted interventions to manage rising incidence, particularly in lower SDI regions.

Relationships between the SDI and the disease burden of MSMI

The relationship SDI and age-standardized DALYs rate (ASDR) for MSMI across various countries and territories in 2021 demonstrated a significant inverse correlation (r = -0.715, p 5A). Countries with lower SDI values, such as Somalia, Chad, and the Central African Republic, had the highest ASDRs, exceeding 400 per 100,000 people, reflecting inadequate healthcare infrastructure and poor socio-economic conditions. Middle-SDI countries like Afghanistan, Madagascar, and Zimbabwe had moderate ASDRs (100–300 per 100,000), showing improvements in healthcare and socio-economic conditions but still facing significant disease burdens. High-SDI countries, such as those in Western Europe, North America, and East Asia, had the lowest ASDRs (below 50 per 100,000), benefiting from advanced healthcare systems and better maternal care.

Similarly, the SDI-ASR relationship from 1990 to 2021 also showed a significant inverse correlation (r = -0.744, p 5B). Low-SDI countries, particularly in Central and Sub-Saharan Africa, had the highest ASRs, exceeding 300 per 100,000, while middle-SDI countries, including those in South Asia and Latin America, had moderate ASRs (100–300 per 100,000). High-SDI countries, including those in Western Europe, North America, and East Asia, exhibited the lowest ASRs, often below 50 per 100,000.

Frontier analysis involving the SDI and MSMI burden

Figure 6A illustrates the ASR for MSMI across various countries from 1990 to 2021, plotted against SDI. The frontier line represents the expected ASR based on SDI, serving as a benchmark for comparison. As SDI increases, the ASR generally decreases and becomes more stable, with the frontier trend stabilizing once SDI exceeds 0.5, indicating more consistent ASR values in countries above this threshold.

Figure 6B highlights disparities in ASR among countries with similar SDI levels in 2021. For instance, Albania (SDI 0.71) had an ASR of 1.75, much lower than American Samoa (SDI 0.72, ASR 14.58). Similarly, the Central African Republic (SDI 0.31, ASR 337.35) had a much higher ASR than Mozambique (SDI 0.32, ASR 50.38). The top five countries with the largest effective difference (EF) from the frontier, ranging from 138.91 to 66.72, were Chad, the Central African Republic, the Democratic Republic of the Congo, Eritrea, and Mali, indicating urgent need for health interventions. Notably, only five countries—Australia, Niue, American Samoa, Kiribati, and the Marshall Islands—saw an increase in ASR. Australia, with an EF of 0.99, showed the smallest deviation between observed and expected ASR, suggesting relatively effective healthcare interventions. The other four countries had higher EF values (ranging from 10.96 to 98.25), reflecting significant public health challenges.

ARIMA forecasting of MSMI to 2040

The analysis of the provided data revealed significant epidemiological trends. In Fig. 7A, the number of cases starts at approximately 20 million in 1990 and fluctuates until 2021. After 2021, the forecasted number of cases has shown a downward trend, reaching approximately 15 million by 2040. This decrease suggests a reduction in the burden of the condition, likely influenced by effective public health measures and improvements in disease management. Moreover, Fig. 7B shows the ASR, which begins at approximately 600 per 100,000 people in 1990 and steadily declines to approximately 494 per 100,000 people by 2021. The forecasting data after 2021 continue to show a downward trend, with the ASR decreasing to approximately 200 per 100,000 by 2040. This declining ASR indicates that when adjusting for the age structure of the population, the risk of developing the disease is decreasing, which suggests effective public health interventions and improvements in disease management.