Original Research

Analysing space-time patterns of maternal mortality attributed to anaemia in Karnataka, India: a spatial epidemiological study

Abstract

Background Maternal health is a globally important health challenge and is the key indicator of healthcare services in any given region. One of the main objectives of Sustainable Development Goal 3.1 is to reduce the global maternal mortality ratio to less than 70 per 1-lakh live births. Most data on maternal mortality are collected and analysed on global, national and subnational levels and regional levels are lacking. Anaemia is one of the major causes of maternal death in India and its data visualisation using geospatial mapping plays a significant role in addressing the emerging need for improved spatial investigation. Geospatial studies of maternal mortality can help policy-makers to prioritise resources by pinpointing geographical areas for implementation.

Methodology Spatial data analysis is effectively used in assessing the spatial distribution of maternal deaths, which are attributed to anaemia as a risk factor for maternal deaths. The data on maternal deaths in Karnataka were acquired and analysed at district level for the years 2017–2022 and thematic maps were generated in geographical information system environment. Further, areal interpolation analysis was explored in deriving the layers that predict the underlying risk of maternal deaths attributed to anaemia in the present study using the available data.

Results Five out of 30 districts showed more than 10% of maternal deaths attributed to anaemia during 2017–2020 while these numbers were increased to 10 during 2020–2021 and later reduced to 6 districts during 2021–2022. Areal interpolation revealed the highest risk areas of maternal deaths attributed to anaemia in Karnataka for the past 5 years (2017–2018 to 2021–2022).

Conclusion Study concluded that by providing a spatial perspective, geospatial analysis has the potential to transform maternal healthcare. Anaemia-related maternal deaths can be minimised by providing specific interventions among disadvantaged women in the Karnataka region.

What is already known on this topic

  • It is already known that maternal health is a critical worldwide issue, with maternal mortality ratio (MMR) serving as a key indicator of healthcare service effectiveness. Anaemia is recognised as one of the major causes of maternal deaths in many regions of low-income and middle-income countries. Anaemia is a preventable and treatable condition if diagnosed early. A much required awareness and training programmes are in great demand for targeted interventions for anaemia prevention and treatment.

What this study adds

  • This study adds to the existing knowledge by specifically focusing on the spatial distribution of maternal deaths attributed to anaemia in Karnataka, India. Spatial insights aid in identifying high-risk regions easily using geographical information system analysis for the already existing data. These findings underscore the importance of incorporating spatial perspectives in maternal healthcare for effective resource allocation and mortality reduction.

How this study might affect research, practice or policy

  • Geospatial mapping and analysis is a cost-effective approach to research in identifying high-risk regions for MMR attributed to anaemia that could lead to more targeted research efforts and interventions focused on these regions. This assists the health administrators and policy-makers in decision-making and developing efficient policies and strategies for improving maternal healthcare services.

Introduction

Maternal health is a critical component of overall public health, as it affects not only the health and well-being of a mother but also on health outcomes of children. If proper care is not taken, pregnancy and childbirth can continue to be a significant cause of morbidity and mortality among women.1 However, most of these maternal deaths are preventable if identified and treated at earlier stages. The baby, family and society may be affected medically or psychologically by the mother’s death.2 Maternal deaths in developing countries are more excessive than those in developed countries. Haemorrhage, sepsis, hypertension in pregnancy, unsafe abortion and difficulties during delivery are some of the major causes of maternal deaths recorded in India. Anaemia is one of the major causes of maternal death. It also plays a role in maternal fatalities brought on by haemorrhage, septicaemia, eclampsia, malaria, hookworms and persistent infection.

Anaemia during pregnancy can lead to morbidity and mortality of the mother and fetus and can have an adverse effect on them.3 The WHO has recognised anaemia as a significant health concern and recommends regular screening and treatment for pregnant women.4 The fear of postpartum depression, premature birth, miscarriage, low birth weight and complications in neurodevelopment outcomes in neonates is more commonly noticed with anaemia during pregnancy.5 Most data on maternal deaths were analysed on global, national and subnational (state) levels, but regional levels were lacking. Data visualisation of maternal deaths through maps portrays the large complex data in simple and easily understandable formats that improve the analysis in a better scientific way and address emerging needs of specific region investigations in coming years. Maternal death events in different time periods can be easily analysed and can locate the hotspot areas through geospatial analytics, rather than the traditional type of data presentation such as tables and charts. This could bring innovative ideas to overcome the problem and take intervention measures by policy planners and decision-makers.

Maternal anaemia can cause serious consequences for both mother and the developing fetus. Fatigue, weakness, dizziness and even heart-related ailments for the mother; whereas it can cause inadequate oxygen supply, impaired motor development, low birth weight, delayed growth and cognition for the developing fetus.6 Awareness programmes about maternal anaemia play an important role in educating the community’s healthcare professionals and policy-makers about the need of preventing and managing maternal anaemia. These awareness programmes aim to educate the society about the causes, consequences and risks of maternal anaemia, which further promotes the strategies for prevention and brings early interventions to decrease the maternal anaemia.7

The 65th World Health Assembly made a commitment to halving the prevalence of anaemia in women of reproductive age (15–49 years) by 2025 when it set global objectives for maternity, baby and early child nutrition in 2012.7 In order to be in line with the Sustainable Development Goals (SDGs) of the United Nations (UN), WHO and United Nations Children’s Fund (UNICEF) proposed extending this aim to 2030.8 Indicator 2.2.3 of the SDGs was introduced for the prevalence of anaemia in women between the ages of 15 and 49 in 2020.9

So, in this study, we intended to analyse the maternal deaths that occurred in Karnataka between 2017 and 2022 which were probably attributed to anaemia through spatial analysis and identify the high-risk regions to be targeted for intervention to reduce the burden of anaemia and help the policy-makers to prioritise the resources.

Methodology

Study design

The present study employed a spatial epidemiological study design to investigate the maternal deaths attributed to anaemia in Karnataka, India.

Setting

This was a secondary data from Directorate of Health and Family Welfare database, Government of Karnataka about maternal deaths reported in 30 districts of Karnataka from 2017–2018 to 2021–2022.

Variables

The obtained non-spatial data contained socioeconomic status, place of death, place of antenatal care, place of delivery, direct and indirect causes of death and time of death of the mother whether during pregnancy, childbirth or within 42 days after childbirth. Maternal deaths are the primary outcome variable, specifically those attributed to anaemia, recorded at the district level in Karnataka from 2017 to 2022. Details of causes of maternal deaths such as heart disease complications, anaemia, endocrinal disorders, infectious diseases, renal conditions, abortions, antepartum haemorrhage, obstructed labour, primary postpartum haemorrhage (PPH), secondary PPH, hypertension during pregnancy, sepsis, complications of anaesthesia, surgical complications, transfusion reaction and sudden deaths were provided in the data collected from which we have selected the deaths that were due to anaemia. District-wise percentage of maternal deaths attributed to anaemia was calculated and used for further spatial analysis. This study considered the prevalence of anaemia among pregnant women in Karnataka as a potential explanatory variable. Spatial data such as district boundaries, taluk boundaries were also considered in the study.

Data sources

Maternal death data were collected from Maternal Health Division, Directorate of Health and Family Welfare Services, Government of Karnataka for the period of 2017–2018 to 2021–2022. District health office of each district collects and maintains the details of each maternal death. The state Maternal Health Division will collect monthly reports from all 30 districts of Karnataka and maintain the overall data for the entire state. We extracted the district-wise percentage of anaemia in pregnant women from National Family Health Survey 5 (NFHS-5) reports.

Spatial data sources

District boundary and taluk boundary shapefiles of Karnataka were downloaded from K-geographical information system (GIS) portal, of Government of Karnataka website.

Study sample size

Study considered all maternal deaths reported in Karnataka during the year 2017–2022. During the study period, the state of Karnataka reported a total of 3307 maternal deaths further spatial analysis was done for the 224 maternal deaths attributed to anaemia as primary cause of death.

Quantitative variables

The number of maternal deaths attributed to anaemia in each district, total number of maternal deaths in each district and percentage of anaemic pregnant women in each district were the main quantitative variables considered in the present study.

Statistical methods

Line graph of year-wise percentage of maternal deaths attributed to anaemia was plotted employing Microsoft—Excel.

Formula used for calculating percentage of maternal deaths attributed to anaemia is given below

Display Formula

Where MMA (maternal mortality attributed to anaemia) is the percentage of maternal deaths attributed to anaemia in each district.

Spatial analysis

Thematic maps were effectively used for visualising the spatial patterns and variations in data. Thematic mapping is a type of geovisualisation used to portray geographical distribution of one or more phenomena, by employing different colours or shades to indicate varying levels of risk across geographical regions. Thematic maps are commonly used by cartographers to create maps that aid in recognising complex spatial patterns of the spatial data and provide specific information about particular locations, which helps in decision-making. Thematic maps were prepared year wise for all 5 years (2017–2018 to 2021–2022) for exploring the spatial distribution of percentage of maternal deaths that were attributed to anaemia as a significant cause using ArcGIS v10 software licensed to JSS AHER.

Areal Interpolation

To predict the underlying risk of anaemia in maternal deaths for a particular district, risk area layers were constructed using areal interpolation. The ArcGIS geostatistical analyst was used to process areal interpolation, which is a geostatistical interpolation technique, to apply kriging theory to data averaged or aggregated over polygons. Prediction and SE values were most effectively calculated in areal interpolation analysis that formed a new set of polygon acquired from all 30-region points within the study area map. Areal interpolation is the process of making estimates from source polygons to an overlapping but incongruent set of target polygons.10 11

Areal interpolation consists of a sequential two-step process. In the initial step, a continuous predictive surface for individual points was generated using source polygons. Subsequently, this predictive surface undergoes aggregation, being applied to the target polygons. The development of the predictive surface preceded the subsequent reaggregation for a distinct set of polygons. Areal interpolation map was generated for the average of 5 years data. Thematic map of distribution of anaemia in pregnant women with the percentage of maternal deaths attributed to anaemia was produced to check for the association.

Results

Temporal trend of the proportion of annual deaths attributed to anaemia in Karnataka (2017–2022)

The annual percentage of maternal deaths attributed to anaemia in Karnataka declined from 2017–2018 to 2019–2020 while the same increased during 2020–2021 and 2021–2022. The highest percentage of maternal deaths attributed to anaemia was during 2017–2018 with 7.87% and the lowest was during 2019–2020 with 5.07%. Percentage of maternal deaths attributed to anaemia during 2021 and 2022 increased to 7.7% (figure 1a).

Figure 1
Figure 1

(a) Trends and (b) Temporal maps of maternal deaths percentage attributed to anaemia in Karnataka, India (2017–2022).

District-wise spatial distribution of maternal deaths attributed to anaemia

As per the thematic map for the year 2017–2018, three districts (Bidar, Kodagu and Bangalore Urban) had more than 15% of maternal deaths attributed to anaemia and two districts had 10%–15% of maternal deaths attributed to anaemia. For the years 2018–2019, only one district, that is, Bagalkote had 39% of maternal deaths attributed to anaemia and four districts, that is, Yadgir, Davangere, Mysuru, Hassan had 10%–15% of maternal deaths attributed to anaemia whereas; Kodagu, Bangalore urban and Bidar which showed highest percentage in the previous year had zero maternal deaths attributed to anaemia. For the year 2019–2020, Hassan had 44.4% of maternal deaths attributed to anaemia and three other districts (Shimoga, Davangere and Bellary) had 10%–15% of maternal deaths attributed to anaemia. For the years 2020–2021, five districts (Bagalkote, Koppal, Davangere, Ramanagara and Kodagu) had more than 15% of the maternal deaths attributed to anaemia and five districts (Bidar, Kalburgi, Ballari, Haveri and Tumkur) had 10%–15% of maternal deaths attributed to anaemia. For the year, 2021–2022, five districts (Bidar, Vijayapura, Haveri, Davangere and Ballari) had more than 15% of maternal deaths attributed to anaemia (figure 1b).

Interpolation analysis

Areal interpolation was carried out to build the layers that predict the underlying risk of anaemia in maternal deaths for a specific district using the 5-year average percentage of maternal deaths attributed to anaemia in each district. All the districts of Karnataka were considered for areal interpolation and the results illustrate that the highest risk was found in the northwest, middle and southwest regions of Karnataka (figure 2). The variogram analysis showed that the actual data points (empirical covariance) fell within the expected range (CIs) of the prediction model (figure 3a). This suggested that the model accurately predicted the spatial distribution of maternal deaths attributed to anaemia in Karnataka. The normal QQ (Quantile-Quantile) plot compared the distribution of standardised errors from the model to a theoretical normal distribution. The plot showed that the standardised errors closely followed the diagonal line, indicating the data were approximately normally distributed (figure 3b).

Figure 2
Figure 2

Areal interpolation map of percentage of maternal deaths attributed to anaemia in Karnataka, India (2017–2022).

Figure 3
Figure 3

(a) Variogram and (b) Normal QQ (Quantile-Quantile) plot analysis for aerial interpolation model accuracy of figure 2.

Distribution of maternal anaemia in Karnataka (NFHS-5)

Average percentage of maternal deaths attributed to anaemia studied for 5 years (2017–2022) was represented along with the prevalence percentage of anaemia among pregnant women from NFHS-5 survey conducted during 2019–2021 (figure 4) in ArcGIS platform. The thematic map representing the percentage of anaemia in pregnant women revealed distinct spatial patterns, with areas in green indicating lower percentages and those in red indicating higher percentages. This suggested significant geographical variation in the prevalence of anaemia among pregnant women across Karnataka. The highest prevalence (more than 50%) was observed in eleven districts (figure 4). The accompanying bar graph depicting the percentage of maternal deaths attributed to anaemia showed a similar trend, with taller bars indicating a higher percentage of maternal deaths attributed to anaemia in certain districts. The region where the prevalence of anaemia in pregnant women was highest was also the region, which was obtained as a hotspot for maternal deaths attributed to anaemia from areal interpolation. The spatial correlation between the prevalence of anaemia in pregnant women and maternal deaths attributed to anaemia underscores the importance of targeted interventions in districts with high prevalence rates to reduce maternal mortality rates associated with anaemia.

Figure 4
Figure 4

Percentage of anaemic pregnant women in Karnataka (NFHS-5) with percentage of maternal deaths attributed to anaemia. NFHS-5, National Family Health Survey 5.

Discussion

Maternal mortality remains a global health concern with anaemia as a significant contributing factor. Earlier research has highlighted that multipronged approach can reduce the burden of maternal mortality. Worldwide anaemia is identified, as the leading cause of maternal mortality in numerous regions. Globally, more than 500 million women between the ages of 15 and 49 were affected by anaemia in 2019. Anaemia is a crucial health problem among pregnant women in India, including the state of Karnataka. Preterm birth, low birth weight, and maternal and fetal morbidity and mortality were all enhanced by maternal anaemia. Iron deficiency is more prevalent than anaemia, and it frequently emerges during early pregnancy, even in women who have sufficient iron scores at starting stage of pregnancy.12 According to the data from the NFHS-5 conducted in 2019–2021, prevalence of anaemia in women of reproductive age was 29.9%. The prevalence was 29.6% for non-pregnant women of reproductive age, whereas it was 36.5% for pregnant women. While the prevalence of anaemia among women of reproductive age has decreased significantly internationally since 2000, it has remained steady among pregnant women.13

It is important to note that these figures can change over time, and continuous efforts are needed to improve maternal health and reduce the risk of anaemia-related complications during pregnancy. Iron-deficiency anaemia and folate-deficiency megaloblastic anaemia are the most prevalent types of anaemia during pregnancy. The latter is more common in women who have insufficient dietary intake and do not receive adequate prenatal iron and folate supplements.14 A study carried out in Mekele town Ethiopia, in 2014 found that parity, meal frequency, dietary variety and meat consumption significantly affected pregnant women’s anaemia.15 These findings underscore the importance of government initiatives such as POSHAN Abhiyaan, National Nutrition Strategy and Anaemia Mukt Bharath launched during 2018 in India aimed to reduce anaemia prevalence among vulnerable groups. Karnataka’s Anaemia Muktha Poustika Karnataka aligns with national guidelines to address anaemia locally, highlighting the need for ongoing targeted polices, especially in rural and marginalised areas.16

Our study has attempted to look into the spatial dimension of maternal deaths attributed to anaemia with the aim of uncovering geographic patterns and identifying high-risk areas. Existing studies often lack spatial granularity, hindering the identification of localised risk factors and specific targeted interventions in these areas. By employing spatial analysis techniques, we seek to provide GIS insights that are essential and crucial for formulation of policies and specific targeted interventions. The results revealed that, districts differed in the percentage of maternal fatalities related to anaemia, with some districts of Karnataka reporting high prevalence of anaemia-related maternal deaths. The study presented areal interpolation tool in mapping of underlying risk of anaemia in maternal deaths for Karnataka state (figure 2) and the highest risks were noticed in northwest, middle and southwest regions.

In the first objective, temporal trend of maternal deaths attributed to anaemia yields a declining trend as various programmes were implemented between 2018 and 2020 including the iron and folic acid supplementation programme, village health and nutrition day, national iron+ initiative and anaemia Mukt Bharat.17 However, the years 2020–2021 and 2021–2022 have seen arise, probably the impact of COVID-19 pandemic, which has disrupted the healthcare system worldwide, including challenges to essential antenatal care services. Several studies conducted to study the impact of COVID-19 pandemic on maternal health and barriers faced by pregnant women to access healthcare during pandemic observed that pandemic resulted in deteriorated maternal and fetal outcomes on a global scale, with an upsurge in maternal deaths, stillbirths, ruptures ectopic pregnancies and maternal depression. Notably, there was a significant variation in certain outcomes between regions with abundant resources and those with limited resources.18–21 Despite the immediate impact of sickness, the COVID-19 pandemic exacerbated and amplified the already existing socioeconomic and health disparities.22 The global lockdowns, movement restrictions, fear of infection, healthcare system strain have led to destruction in antenatal services, thereby reducing the number of clinical visits or delay in seeking the screening and treatment for anaemia from healthcare centres. As the pandemic situation came under control by the end of 2022, the health services stabilised and the antenatal services were also re-established with due time.

While the burden of anaemia on maternal deaths has decreased on yearly basis, individual districts displayed variation across different years. Even though the burden of maternal anaemia has reduced in Karnataka, it remained high in certain regions or districts that clearly indicated the spatial disparities. The factors associated with maternal mortality were region or space-specific, and the use of geospatial analysis in maternal mortality and morbidity is still limited.23 Those districts identified as high-risk areas in the year 2017–2018 has shown decline in the subsequent year, probably reasons could be the multisectoral approach of the government initiatives. The number of districts that have been identified with more than 15% of maternal deaths attributed to anaemia was more than 10 in 2020–2021, this was probably because of the impact of COVID-19 pandemic, which disrupted the healthcare services as mentioned above. Once the system had been established, we saw a static percentage of maternal deaths attributed to anaemia of 7.7% during 2021–2022. Further, districts like Chikkamagaluru, Dakshina Kannada, Gadag and Udupi reported zero maternal death attributed to anaemia throughout the study period. Similar to our study, study conducted in Ethiopia aimed to observe that over one third of pregnant women were anaemic and the prevalence varied among Ethiopian administrative zones.24 Another study in Kenya showed that the accurate mapping of maternal health outcomes using routinely collected data was important for addressing subcountry disparities.25

Given the greater precision and detail afforded by areal interpolation compared with traditional thematic mapping, we opted to continue our analysis using areal interpolation methods. This technique has identified the regions near the districts of Bidar, Bagalkot, Bellary, Davangere, Kodagu and Haveri as the very highest risk areas and vulnerable populations while Gadag, Udupi, Dakshina Kannada, Chikkamagaluru and Chitradurga showed least risks. Sociodemographic characteristics identified in the NFHS 5 survey such as the high prevalence of anaemia among pregnant women (40%–60%), low body mass index among women (12%–25%), low levels of education (39%–58%), early marriage (12%–28%) and low coverage of health insurance schemes (15%–20%) were crucial factors. Additionally, lower rates of consumption of iron folic acid (IFA) supplementation among pregnant women for 180 days (16%–30%) underscore potential challenges. These factors collectively may contribute to MMA in high-risk districts. This insight for public health practice has facilitated evidence-based decision-making, where the policy-makers can design specific targeted interventions for these areas considering the local sociocultural background of the vulnerable population and allocate the resources efficiently, monitor the impact of this public health programme over the period.

According to the NFHS-5 study, pregnant women’s anaemia was most prevalent in Bidar, Chitradurga, Dharwad, Gadag, Haveri, Kalaburagi, Kodagu, Koppal, Raichur, Vijayapura and Yadgir. Further, to add the percentage of pregnant women who took IFA for at least 100 days during pregnancy was between 32% and 45% and for at least 180 days was between 15% and 25%.26–28 This could have led to a higher proportion of maternal deaths attributed to anaemia in these areas, thus, our study results correlate with the NFHS-5 survey. Similar study carried out in Tanzania using inverse distance weighted interpolation method found geographical differences in patterns of death.29 Another study conducted in Mozambique used spatial zero-inflated models where maps were used to highlight areas with increased or decreased mortality rate and such areas were found in south and north of Mozambique.30

Very few studies have focused on the spatial analysis of maternal anaemia in India, particularly in Karnataka. Furthermore, among the limited studies conducted in Karnataka, especially on maternal anaemia, we were able to identify this particular study conducted in North Karnataka focusing on anaemia in pregnant women. Study included 500 pregnant women and results from the study revealed that 93.4% were urban dwellers and sociodemographic parameters like age, residence, family size, education level and family income, with the exception of religion, seemed to be strongly associated with anaemia.31 According to research conducted in 2008, there was a statistically significant difference between the anaemia prevalence between employed women and homemakers.32 There was a variation in the distribution of anaemia in lower-income groups. Anaemia prevalence and economic growth were negatively associated at the national level. Education, money, occupation (such as agricultural labourers) and place of living all had an impact on anaemia societal patterns. Anaemia is typically a sign of socioeconomic deprivation; those with the lowest levels of education and income were most likely to be exposed to risk factors for anaemia and its after-effects.

Geospatial analysis offers numerous advantages over traditional methods in analysing maternal deaths. By providing a spatial perspective, integrating multiple data sources, identifying high-risk populations, enabling real-time decision-making and improving data communication, geospatial analysis has the potential to transform maternal healthcare. Geospatial analysis is a tool, which helps in decision-making for policy-makers by identifying geographically high maternal mortality and priority area.33 Areal interpolation along with the thematic mapping, has shown variations in the burden of MMA. Moreover, areal interpolation enables the integration of diverse data sources fostering collaboration across multiple sectors and the need for interdisciplinary approach to enhance the effectiveness of public health efforts, address the health disparities in combating anaemia and improve the overall health outcomes of pregnancy.

Conclusion

The spatiotemporal (district and year-wise) thematic maps generated in this study highlighted the spatial distribution of maternal deaths attributed to anaemia in Karnataka, revealing areas of high prevalence. Areal interpolation further identified regions with the highest risk of maternal deaths attributed to anaemia, aiding in the prioritising of resources for targeted intervention. Overall, the best use of scarce resources and governmental directives could be implemented in high-risk locations by taking into account of these space-time patterns.

Limitations

The effectiveness of geospatial analysis relies on the quality and availability of spatial data. This study did not account for external factors such as cultural or economic issues, which may influence maternal health outcomes independently of geographical location.