García‑Tizón Larroca et al. BMC Public Health (2022) 22:337 https://doi.org/10.1186/s12889-022-12686-z RESEARCH Maternal mortality trends in Spain during the 2000-2018 period: the role of maternal origin Santiago García‑Tizón Larroca1*, Juan Arévalo‑Serrano2, Maria Ruiz Minaya1, Pilar Paya Martinez1, Ricardo Perez Fernandez Pacheco1, Santiago Lizarraga Bonelli1 and Juan De Leon Luis1  Abstract  Background:  The available literature indicates that there are significant differences in maternal mortality according to maternal origin in high income countries. The aim of this study was to examine the trend in the maternal mortality rate and its most common causes in Spain in recent years and to analyse its relationship with maternal origin. Methods:  This was a cross-sectional study of all live births as well as those resulting in maternal death in Spain dur‑ ing the period between 2000 and 2018. A descriptive analysis of the maternal mortality rate by cause, region of birth, maternal age, marital status, human development index and continent of maternal origin was performed. The risk of maternal death was calculated using univariate and multivariate logistic regression analyses, with adjustment for certain variables included in the descriptive analysis. Results:  There was a total of 293 maternal deaths and 8,439,324 live births during the study period. The most com‑ mon cause of maternal death was hypertensive disorders of pregnancy. The average maternal death rate was 3.47 per 100,000 live births. The risk of suffering from this complication was higher for immigrant women from less developed countries. The adjusted effect of maternal HDI score over maternal mortality was OR = 0.976; 95% CI 0.95 – 0.99; p = 0.048; therefore, a decrease of 0.01 in the maternal human development index score significantly increased the risk of this complication by 2.4%. Conclusions:  The results of this study indicate that there are inequalities in maternal mortality according to maternal origin in Spain. The human development index of the country of maternal origin could be a useful tool when estimat‑ ing the risk of this complication, taking into account the origin of the pregnant woman. © The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://​creat​iveco​mmons.​org/​licen​ses/​by/4.​0/. The Creative Commons Public Domain Dedication waiver (http://​creat​iveco​ mmons.​org/​publi​cdoma​in/​zero/1.​0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Background Maternal mortality is one of the most sensitive indica- tors of the quality of health care in each country [1]. This complication of pregnancy is catastrophic both for families and for society in general, constituting an impor- tant public and social health problem. This is aggravated in  situations where certain factors such as economic, educational and legal inequality or the lack of opportuni- ties for a specific group of women entail an increased risk of this pregnancy outcome [2]. Despite the decrease in the rate of maternal mortal- ity in recent years, there is still a lack of significant pro- gress in reducing the frequency of preventable causes of maternal death due to multiple and complex factors. This results in an estimate of approximately 300,000 mater- nal deaths per year worldwide due to pregnancy, child- birth and postpartum complications [3]. In 2015, the Open Access *Correspondence: gineteca@gmail.com 1 Department of Obstetrics and Gynaecology, Hospital General Universitario Gregorio Marañón, Universidad Complutense de Madrid, O’donnell 48, 28029 Madrid, Spain Full list of author information is available at the end of the article http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/publicdomain/zero/1.0/ http://creativecommons.org/publicdomain/zero/1.0/ http://crossmark.crossref.org/dialog/?doi=10.1186/s12889-022-12686-z&domain=pdf Page 2 of 10García‑Tizón Larroca et al. BMC Public Health (2022) 22:337 World Health Organization (WHO) released “Strategies towards ending preventable maternal mortality (EPMM)” (EPMM Strategies), a direction-setting report indicating global targets and strategies for reducing maternal mor- tality in the Sustainable Development Goal (SDG) period [4]. In this regard, several countries and international agencies have previously sought, through the Millennium Development Goals (MDGs), to improve the lives of peo- ple in more disadvantaged countries by globally reducing the rate of maternal death, among other objectives [5]. The monitoring of the progress of the MDG 5 when measuring the variations in the maternal death rate has shown that many countries lack quality data for the quantification of this complication. The UN’s Maternal Mortality Estimation Inter-Agency Group (consisting of the WHO, UNICEF, UNFPA, World Bank Group, and UNPD) has tried to produce reliable data on maternal mortality in each country since 1990 [6–8]. In this regard, the causes of maternal death are not always well recorded or identified. With data collected between 2003 and 2009 in 115 countries, Say et  al. [9] were able to verify that approximately 70% of mater- nal mortality events were due to direct obstetric causes. However, the study data showed that these were incom- plete and that the indirect causes were not well defined in up to one-fifth of the cases [9]. In addition to the causes of maternal death, there are certain socioeconomic and sociodemographic factors related to the lifestyle of women that can influence the outcome of their pregnancy. Maternal origin and immi- gration are particularly relevant. Several authors have studied the influence of immigrant women on public health in destination countries, espe- cially in Europe and North America. Obstetric outcomes appear to be worse in pregnant immigrants than in native women in Western countries. The published results are heterogeneous mainly due to the different ways of clas- sifying immigrant women, either by race, country of ori- gin or socioeconomic level of the place of origin [10–12]. Some authors have proposed using the human develop- ment index (HDI) of the country of maternal origin to classify pregnant women. This index collects very rel- evant information on the socioeconomic situation of the country of origin and its citizens, such as having a long and healthy life, acquiring knowledge and having a decent standard of living [13]. The HDI is prepared annually by the United Nations Development Program (UNDP), assigning a score of 0 to 1 and classifying each country into one of 4 groups: very high HDI, high HDI, medium HDI and low HDI. There are other sociodemo- graphic indices that reflect the situation of development, progress and absence of inequality among citizens of the same country, such as the gender inequality index (GII). This index measures the lost human development in 3 important dimensions, i.e., reproductive health, politi- cal empowerment, and economic status, reflecting the distance required for a society to achieve full equality between women and men [14]. The correct classification of immigrant women is extremely important because their risk of severe morbid- ity and maternal mortality is increased when compared with that for the native population in developed coun- tries [15]. The main objective of this study was to analyse the trend in the maternal mortality rate in Spain in recent years and to identify certain sociodemographic factors that could influence it, such as maternal origin, through different forms of classification. Methods This was a cross-sectional study with data from all live births and the pregnancies that resulted in maternal death in Spain during the 2000-2018 period. The infor- mation was provided by the Spanish National Institute of Statistics (INE, for its abbreviation in Spanish) upon spe- cific request by the authors. The INE approved this data to be published (reference number PB063/2021). Infor- mation was collected on the region of Spain where the delivery occurred and the year of delivery, maternal age, maternal marital status, continent of maternal origin, HDI of the country of maternal origin, GII of the country of maternal origin and the cause of maternal death classi- fied based on the ICD-10. First, the maternal mortality rate was calculated using the number of annual maternal deaths per 100,000 live births to assess trends during the study period. The defi- nition of maternal death used in this study was that given by the WHO: The death of a woman while she is pregnant or within 42 days after the termination of the preg- nancy, regardless of the duration and site of preg- nancy, due to any cause related to or aggravated by the pregnancy itself or its care, but not due to acci- dental or incidental causes [16]. In Spain, every maternal death must be reported to the INE through 3 documents: medical death certificate, which is filled out by the healthcare professional with the cause and the date of maternal death in accordance with the latest WHO recommendations, the statistical bulletin of judicial death and the statistical bulletin of childbirth. A descriptive analysis of the sample was performed by calculating maternal mortality rates by population groups of pregnant women based on the cause of mater- nal death, the region of Spain where the birth occurred, the maternal age range, the maternal marital status, the Page 3 of 10García‑Tizón Larroca et al. BMC Public Health (2022) 22:337 maternal HDI group (1-very high, 2-high, 3-medium, and 4-low) and the continent of maternal origin (Europe, America, Africa, and Asia). An initial comparative analysis was performed between 2 groups of pregnant women based on their belonging to more developed HDI groups (groups 1 and 2) and less developed HDI groups (groups 2 and 3) based on varia- bles such as maternal age, maternal marital status, mater- nal GII and the most common causes of maternal death (haemorrhage, hypertensive disorders of pregnancy, infection and sepsis, amniotic fluid embolism, abortion and obstetric thromboembolism). Linear regression analysis was carried out initially between the HDI variables of the country of maternal origin and the maternal mortality rate and between the GII of the country of maternal origin and the maternal death rate to assess the relationship between them. Last, logistic regression analysis was performed using the following variables: continent of maternal origin, year in which birth occurred, maternal HDI, maternal HDI group and maternal GII. In addition, a new variable, HDI100, was created, resulting from multiplying the HDI score by 100. Indicator variables were used, with the cat- egory with the lowest maternal mortality serving as the reference. In this way, univariate analysis was performed with each of the variables, and multivariate analysis was performed with all variables. The effect of maternal HDI score over maternal mor- tality was adjusted using backward estimative multivari- ate binary logistic regression with the predictors year in which birth occurred, immigrant status, continent of maternal origin and GII. Variable selection in the mul- tivariate regression model was performed according to subject matter knowledge as predictors of maternal mor- tality. The order of selection to evaluate the inclusion or exclusion of the predictors was by descending statisti- cal significance. The criteria taken to maintain or retire the predictors was the clinical significance, that is, the change of more or less than 10% of maternal HDI OR. The results were expressed as odds ratios (ORs) with a 95% confidence interval, and p values < 0.05 were consid- ered significant. All statistical analyses were carried out using STATA version 15.0 (Stata Corp, College Station, TX). Results During the study period, data from 8,439,324 live births and 293 maternal deaths were collected; the data indi- cated that the average maternal mortality rate was 3.47 per 100,000 live births in Spain. Figure 1 shows a slightly decreasing trend in the rate of this complication year by year. Table 1 provides the data on the most frequent causes of maternal death in Spain and the rates by region where delivery occurred. The most common cause of death in pregnant women was hypertensive disorders of preg- nancy (19.4% of the total), followed by obstetric haemor- rhage (18.7%). The region of Spain with the lowest rate of this complication was the Chartered Community of Nav- arra, located in the north of Spain, and the region with the highest was Melilla, with an average rate of 19.81 per 100,000 live births. Table  2 provides data on maternal death rates by age group, maternal marital status, HDI group of maternal origin and continent of maternal origin; pregnant women aged 40 years or older, married women, those belonging Fig. 1  Maternal mortality rate trends in Spain during the 2000-2018 period Page 4 of 10García‑Tizón Larroca et al. BMC Public Health (2022) 22:337 to the least developed HDI group (group 4), with a rate of 11.4 per 100,000 live births, and patients of Asian ori- gin had the highest rates of maternal death, respectively. Overall, pregnant immigrants experienced higher rates of maternal death than did native women. Table  3 shows the comparison of cases of maternal death between groups with a higher degree of human development (groups 1 and 2) and groups with a lower HDI (groups 3 and 4) in terms of maternal characteristics and more common causes of maternal death. The only statistically significant differences were the GII for each group. Figures 2 and 3 show, respectively, the trend over time in the rate of maternal death by continent of maternal Table 1  Descriptive analysis of maternal mortality rate by ICD-10 cause, and region of delivery Variables Deaths, n (%) Total live births (n) Per 105 live births (95% CI) ICD-10 cause   Ectopic pregnancy O00 11 (3.75) 8,439,324 0.13 (0.05-0.2)   Pregnancy with abortive outcome (exclud‑ ing ectopic pregnancy) O01-O08 20 (6.82) 8,439,324 0.23 (0.13-0.34)   Oedema, proteinuria and hypertensive disorders of pregnancy, childbirth and the puerperium O10-O16 57 (19.4) 8,439,324 0.67 (0.5-0.85)   Haemorrhage O20 O44.1 O45 O46 O67 O72 55 (18.7) 8,439,324 0.65 (0.47-0.82)   Infection/sepsis O75.2 O75.3 O85 O86 O41.1 21 (7.16) 8,439,324 0.24 (0.14-0.35)   Obstetric blood-clot embolism O22.1 O22.3 O22.5 O22.8 O22.9 O87.0 O87.1 O.87.3 O87.8 O87.9 O88 23 (7.84) 8,439,324 0.27 (0.16-0.38)   Amniotic fluid embolism O88.1 30 (10.2) 8,439,324 0.35 (0.22-0.48)   Complications of anaesthesia O29 O74 O89 2 (0.6) 8,439,324 0.02 (0.00-0.05)   Rupture of uterus O71.0 O71.2 9 (3) 8,439,324 0.1 (0.03-0.17)   Other direct causes 44 (15,01) 8,439,324 0.52 (0.36-0.67)   Indirect causes: Diseases of the circulatory system complicating pregnancy, childbirth and the puerperium 099.4 4 (1.3) 8,439,324 0.04 (0.00-0.09)   Diseases of the circulatory system complicating pregnancy, childbirth and the puerperium O98, O99.1-3, 5-9 7 (2.3) 8,439,324 0.08 (0.02-0.39)   Obstetric death of unspecified cause O95 10 (3.4) 8,439,324 0.11 (0.04-0.19) Region   Andalusia 88 (30) 1,642,208 5.35 (4.23-6.47)   Aragon 12 (4.1) 220,491 5.44 (2.36-8.52)   Balearic Islands 9 (3.1) 206,731 4.35 (1.51-7.2)   Catalonia 46 (15.7) 1,427,482 3.22 (2.3-4.15)   Canary Islands 14 (4.77) 342,649 4.08 (1.94-6.22)   Cantabria 3 (1) 91,215 3.28 (0.43-7.01)   Castilla La Mancha 8 (2.73) 346,581 2.3 (0.71-3.9)   Castile and Leon 12 (4.1) 351,917 3.41 (1.48-5.34)   Community of Madrid 28 (9.55) 1,292,946 2.16 (1.36-2.96)   Chartered Community of Navarra 1 (0.34) 118,432 0.84 (0.08-2.49)   Valencian Community 27 (9.21) 892,936 3.02 (1.88-4.16)   Extremadura 4 (1.36) 183,018 2.18 (0.04-4.32)   Galicia 7 (2.38) 388,203 1.8 (0.46-3.13)   Basque Country 6 (2.04) 370,431 1.62 (0.32-2.91)   Principality of Asturias 10 (3.41) 155,008 6.45 (2.45-10.44)   Region of Murcia 7 (2.38) 315,854 2.21 (0.57-3.85)   La Rioja 3 (1.02) 54,755 5.47 (0.72-11.6)   Ceuta 2 (0.68) 26,393 7.57 (2.92-18.1)   Melilla 6 (2.04) 30,283 19.81 (3.96-35.6) Page 5 of 10García‑Tizón Larroca et al. BMC Public Health (2022) 22:337 origin and HDI group of maternal origin. Compared to the rest of the groups, European pregnant women had the lowest rates of maternal death in all time periods studied, and women belonging to HDI groups 2 and 4 showed the highest rates in the same time intervals. Figure  4 shows the statistically significant relation- ship, based on linear regression analysis, between the HDI of the country of maternal origin and the maternal death rate (y = − 49.447x + 46.329, R2 = 0.5149, p < 0.01), such that the lower was the HDI of maternal origin, the higher was the mater- nal mortality rate. Figure  5 shows the same type of regression analysis between the GII of the country of maternal origin and the maternal mortality rate (y = − 49.447x + 46.329, R2 = 0.5149, p = 0.038); the lower was the GII of maternal origin, the lower was the maternal mortality rate. Table 4 provides the results of the final univariate logis- tic regression analysis taking into account the HDI100 as a variable of interest and the HDI group, GII, year of delivery and continent of maternal origin as potential confounders in the initial maximal model. The model adjusted for these predictor variables indicated that for each 0.01-point decrease in the HDI of maternal origin, the risk of maternal death significantly increased by 2.4%. The result of estimative multivariate logistic regres- sion analysis taking into account the HDI score × 100 as a variable of interest and the immigrant state, GII, year of delivery and continent of maternal origin as potential confounders in the initial maximal model was OR = 0.976; 95% CI 0.95 – 0.99; p = 0.048. The model adjusted for these predictor variables indicated that for each 0.01-point decrease in the HDI of maternal origin, the risk of maternal death significantly increased by 2.4%. Table 2  Descriptive analysis of maternal mortality rate by maternal age, marital status, HDI group, maternal continent of origin and maternal origin Variables Deaths, n (%) Total live births (n) Per 105 live births (95% CI) Maternal Age   ≤ 20 5 (1.7) 210,655 2.37 (0.3-4.45)   20 - 29 60 (20.47) 2,603,323 2.3 (1.72-2.88)   30 – 39 183 (94.8) 5,185,060 3.52 (3.01-4.04)   ≥ 40 45 (15.35) 440,286 10.22 (7.23-13.2) Marital status   Married 208 (71) 5,611,091 3.7 (3.2-4.21)   Not married 85 (29) 2,828,233 3 (2.36-3.64) HDI group   1-Very high 236 (80.54) 7,286,687 3.23 (2.82-3.65)   2-High 33 (11.26) 634,656 5.2 (3.42-6.97)   3-Medium 15 (5.2) 439,037 3.41 (1.68-5.14)   4-Low 9 (3.1) 78,944 11.4 (3.95-18.84) Maternal continent of origin 234 (79.86) 7,236,218 3.23 (2.81-3.64)   America 26 (8.87) 622,458 4.17 (2.57-5.78)   Africa 26 (8.87) 469,946 5.53 (3.4-7.65)   Asia 7 (2.3) 111,702 6.26 (1.6-10.9) Maternal origin   Native 225 (76,8) 6,819,919 3.29 (2.86-3.73)   Immigrant 68 (23.2) 1,619,405 4.2 (3.2-5.19) Table 3  Comparison of cases of maternal death between groups with a higher degree of human development (groups 1 and 2) and groups with a lower HDI (groups 3 and 4) Variable HDI 1-2 HDI 3-4 p value Maternal age, mean (SD) 33.8 (5.76) 32.2 (5.58) 0.19 Not married, n (%) 82 (30.4) 3 (12.5) 0.06 GII, mean (SD) 0.11 (0.1) 0.49 (0.05) < 0.001 Cause of maternal death:   Haemorrhage, n (%) 56 (20.81) 7 (41.2) 0.34   Hypertensive disorders, n (%) 51 (18.9) 6 (25) 0.54   Infection/sepsis, n (%) 20 (7.43) 1 (4.16) 0.55   Amniotic fluid embolism, n (%) 28 (10.4) 1 (4.16) 0.32   Abortive outcome, n (%) 19 (7.06) 1 (4.16) 0.58   Obstetric blood-clot embolism, n (%) 23 (8.55) 1 (4.16) 0.43 Page 6 of 10García‑Tizón Larroca et al. BMC Public Health (2022) 22:337 Fig. 2  Maternal mortality rate by continent of maternal origin and period Fig. 3  Maternal mortality rate by maternal HDI group of maternal origin and period Fig. 4  Relationship between the HDI of the country of maternal origin and maternal death rate Page 7 of 10García‑Tizón Larroca et al. BMC Public Health (2022) 22:337 Discussion To our knowledge, this is the most up-to-date study on maternal mortality data in Spain. Although this mater- nal complication of pregnancy is recorded through the INE, there are no periodic analyses by health institutions that systematically reflect the trend or characteristics of this event in Spain. In this regard, the WHO stated that nations should maximize their efforts in strengthening health systems to collect high-quality data to respond to the needs and priorities of women and girls and ensure accountability to improve the quality of care and equity [17]. The maternal mortality rate in Spain is one of the low- est observed in countries in our region, with slight fluc- tuations year by year, which reflects, in part, the good health care provided for pregnancy, childbirth and post- partum complications and the universal access of the population to this health care. Other countries with sim- ilar or even higher levels of development, such as Nor- way and Canada, show maternal mortality rates in recent years between 5.1 and 12 deaths per 100,000 live births [18, 19]. The increase in the rate of this complication in these countries, such as Canada, was proposed to be the result of improvements in vital statistics registration data and due to the switch from the ICD9 to ICD10 when classifying this complication. In this regard, we do not know if maternal deaths are correctly quantified in Spain, although some authors claim that there may be inade- quate identification and recording of maternal deaths in up to 40% of cases, which would reflect a clear underesti- mation of maternal mortality [20]. One of the most important findings of our research was the identification of the most common causes of maternal death in Spain. The most prevalent causes were hypertensive disorders of pregnancy, closely followed by obstetric haemorrhage. Other causes, in order of fre- quency, were other direct obstetric causes in up to 15% of the cases, amniotic fluid embolism in 10% of cases, infec- tion and sepsis and obstetric thromboembolism; these data allows recognition of the problems that require greater optimization with respect to the allocation of health resources most necessary in Spain. These data do not differ much from those previously published by Fer- nandez et al. [21], who reported that the most prominent causes of maternal death in Spain were hypertensive dis- orders of pregnancy and postpartum complications in 22.6 and 23.3% of cases, respectively. A descriptive analysis of the causes and trends of maternal mortality in Spain during the period between 1999 and 2015 also indicated that the most common causes responsible for this perinatal event were, in order of frequency, obstetric haemorrhage and hyper- tensive disorders of pregnancy [22]. The most relevant research on maternal mortality at the international level was published in 2015, in which a global and regional review of data from 186 countries during the 1990–2015 period identified the 8 main causes of maternal death. The results of the study indicated that, overall, obstet- ric haemorrhage is the most frequent cause of maternal death in most countries and that it is potentially avoid- able with adequate obstetric management as well as the use of appropriate health resources [23]. Our results showed differences in the rate of this complication among the different regions of Spain where delivery occurred. The Chartered Community of Navarra and the Basque Country had the lowest rates while Melilla and Ceuta had the highest rates in the national territory. We do not know the underlying Fig. 5  Relationship between the GII of the country of maternal origin and maternal death rate Page 8 of 10García‑Tizón Larroca et al. BMC Public Health (2022) 22:337 reasons for this situation, although possible factors include greater immigration from Africa in south- ern regions of Spain and each region having its own health system independent of the rest of the national territory. The distinguishing characteristics of differ- ent populations, the influx of immigrants with certain profiles and the inequality in the health benefits of each nation could justify the existence of health inequities in general and in reproductive health specifically among citizens of European countries, as was observed in this study [24, 25]. Maternal age could play an important role in the risk of maternal death, although its influence on this peri- natal outcome was not specifically analysed. The group of women aged 40 years or older had a crude risk on the order of 3 to 5 times higher than that observed for women in other age groups in Spain during the study period. The risk of adverse perinatal events and compli- cations during pregnancy is significantly increased with maternal ages greater than 40 years [26, 27]. Sheen et al. [28] pointed out that women in the age group of 45 years or older were those who had a greater risk of caesarean delivery, preeclampsia, postpartum haemorrhage, gesta- tional diabetes, puerperal thrombosis and hysterectomy as severe complications of pregnancy. When observing maternal death rates by maternal origin, the results of this study revealed very relevant findings regarding its influence on this pregnancy com- plication. First, the rates of maternal death were higher in the HDI groups comprising less developed countries, especially group 4 (very low HDI), with a crude risk 3 to 4 times higher than that for group 1. Regarding the continent of origin, with respect to European pregnant women, the rest of the women had higher rates of mater- nal death, more markedly for those whose continents of origin were Asia and Africa. This finding was already suspected due to previous publications in which mater- nal death and severe acute maternal morbidity events occurred more frequently in foreign women from less developed countries [13, 29]. Through linear regression analysis, we were able to ver- ify that the lower the HDI and the higher the GII of the country of maternal origin, the higher was the maternal death rate, revealing how important it is to conduct fur- ther research on these aspects of development by classi- fying the origin of immigrant women in our country. In addition, when performing multivariate regression analy- sis adjusted for different covariates, we observed that a decrease of 0.01 points in the maternal HDI score gener- ates a significant increase in the risk of maternal death. This allows a more accurate calculation of the added risk that a patient has of dying from pregnancy complications as a function of variations in this variable. The HDI of the country of maternal origin simplifies and captures very important sociodemographic and eco- nomic characteristics regarding the development of each nation and provides a quantitative dimension. This could explain why its use may be valuable when analysing the specific risk of immigrant pregnant women suffering cer- tain complications of pregnancy in developed countries, such as Spain, because maternal origin and various social determinants, such as family income, education level, Table 4  Final univariate logistic regression analysis a Reference Univariate p OR CI 95% Nationality   Non-spanish 0.386 1.27 0.74 – 2.20   Spanisha 1 Continent 0.025 Europea 1 Africa 0.132 1.71 0.85 – 3.44 America 0.411 1.29 0.70 – 2.38 Asia 0.289 1.68 0.65 – 4.37 Other 0.002 26.49 3.34 – 210.02 Year 1.00 2000a 1 2001 0.899 1.19 0.08 – 17.12 2002 0.969 0.95 0.07 – 13.40 2003 0.850 1.29 0.09 – 17.49 2004 0.837 1.31 0.10 – 17.47 2005 0.944 1.10 0.08 – 14.44 2006 0.882 0.82 0.06 – 10.79 2007 0.823 0.75 0.06 – 9.36 2008 0.829 1.31 0.11 – 15.45 2009 0.984 0.98 0.08 – 11.62 2010 0.902 1.17 0.10 – 13.80 2011 0.893 0.84 0.07 – 10.22 2012 0.714 0.63 0.05 – 7.75 2013 0.885 1.20 0.10 – 14.45 2014 0.690 0.60 0.05 – 7.51 2015 0.991 1.01 0.08 – 12.26 2016 0.977 1.04 0.09 – 12.43 2017 0.960 0.94 0.08 – 11.22 2018 0.624 0.53 0.04 – 6.59 GII score × 100 0.172 1.01 0.99 – 1.03 HDI group 0.001 Group 1a 1 Group 2 0.110 1.61 0.90 – 2.87 Group 3 0.894 1.06 0.48 – 2.31 Group 4 < 0.001 5.07 2.28 – 11.53 HDI score ×  100 0.048 0.976 0.95 – 0.99 Page 9 of 10García‑Tizón Larroca et al. BMC Public Health (2022) 22:337 degree of social exclusion and adequate access to emer- gency health services and pregnancy monitoring, have a very influential role in pregnancy outcomes [15, 30, 31]. Regarding the limitations of this study, we recognize that there are several. First, as previously mentioned, it is unknown whether all maternal deaths were correctly reported to the INE during the study period in Spain and whether this issue would result in an underestimation of the rates of this complication. Furthermore, for unclear reasons, there was also a nonnegligible percentage of maternal mortality cases with unspecified causes. As unspecified cases were very infrequent, it is possible that there would not be differences in terms of the character- istics of the pregnant women and the causes of maternal death when comparing higher HDI groups with lower HDI groups. In addition, in the multivariate analysis, the fact that there were relationships that were not signifi- cant can be explained by the fact that there were very few deaths with respect to the large number of births without mortality; therefore, the proportion of maternal deaths in all the groups analysed was very small, and it was difficult to find significant differences. Another limitation of our multivariate analysis model was the lack of adjustment for relevant variables, such as maternal age, body mass index, type of health care centre or pre-existing maternal conditions that are of interest in the study of maternal mortality. Last, cases that fell within the definition of late mater- nal death and those that corresponded to the death of a woman from direct or indirect obstetric causes more than 42 days but less than one year after termination of pregnancy were not included [32]. These cases are equally important due to the very serious social connota- tions and the severe impact that the death of the mother produces on families. Conclusions The maternal mortality rate in Spain is one of the low- est in the world, although it is possible that it is neces- sary to improve data collection systems when reporting this event as well as to periodically analyse its causes and most frequent risk factors in Spain. Maternal mortality occurs more frequently, with a significantly increased risk, in immigrant women from underdeveloped coun- tries. This is why the use of maternal origin classification systems such as the HDI score may more precisely profile the risk of maternal death in pregnant women. This index includes extremely important aspects related to the char- acterization of the sociodemographic profile of patients. Abbreviations EPMM: Ending preventable maternal mortality; GBD: Global Burden of Disease; UN: United Nations; UNICEF: United Nations Children’s Fund; UNFPA: United Nations Fund For Population Activities; UNPD: United Nations Procurement Division; HDI: Human development index; GII: Gender Inequality Index; INE: Instituto Nacional de Estadistica; SDG: Sustainable Development Goal; USA: United States of America; WHO: World Health Organization; ICD: International Classification of Diseases. Acknowledgements Nothing to declare Authors’ contributions GTLS designed, carried out the study and drafted the final manuscript, ASJ performed the statistical analysis, RMM revised the final manuscript, PMP revised the final manuscript. PFPR revised the final manuscript, LBS revised the final manuscript, DLLJ revised the final manuscript. All authors have read and approved the manuscript. Funding This research received no specific grant from any funding agency in the pub‑ lic, commercial or not-for-profit sectors. Availability of data and materials Any additional information regarding the study will be shared upon request by the corresponding author. Declarations Ethics approval and consent to participate This is a cross-sectional study and a secondary data analysis so consent to participate was not required according to spanish legislation. The Spanish National Institute of Statistics (INE) and its Ethics Committe approved this data to be published (reference number PB063/2021). All data obtained by the INE was de-identified so participants’privacy and confidenciality are protected. Permission to access data was granted by INE. (see document attached). All authors declare that this research was performed according to the ethical principles from the Declaration of Helsinki. Consent for publication Not applicable. 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