Elsevier

The Lancet

Volume 384, Issue 9947, 13–19 September 2014, Pages 980-1004
The Lancet

Articles
Global, regional, and national levels and causes of maternal mortality during 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013

https://doi.org/10.1016/S0140-6736(14)60696-6Get rights and content

Summary

Background

The fifth Millennium Development Goal (MDG 5) established the goal of a 75% reduction in the maternal mortality ratio (MMR; number of maternal deaths per 100 000 livebirths) between 1990 and 2015. We aimed to measure levels and track trends in maternal mortality, the key causes contributing to maternal death, and timing of maternal death with respect to delivery.

Methods

We used robust statistical methods including the Cause of Death Ensemble model (CODEm) to analyse a database of data for 7065 site-years and estimate the number of maternal deaths from all causes in 188 countries between 1990 and 2013. We estimated the number of pregnancy-related deaths caused by HIV on the basis of a systematic review of the relative risk of dying during pregnancy for HIV-positive women compared with HIV-negative women. We also estimated the fraction of these deaths aggravated by pregnancy on the basis of a systematic review. To estimate the numbers of maternal deaths due to nine different causes, we identified 61 sources from a systematic review and 943 site-years of vital registration data. We also did a systematic review of reports about the timing of maternal death, identifying 142 sources to use in our analysis. We developed estimates for each country for 1990–2013 using Bayesian meta-regression. We estimated 95% uncertainty intervals (UIs) for all values.

Findings

292 982 (95% UI 261 017–327 792) maternal deaths occurred in 2013, compared with 376 034 (343 483–407 574) in 1990. The global annual rate of change in the MMR was −0·3% (–1·1 to 0·6) from 1990 to 2003, and −2·7% (–3·9 to −1·5) from 2003 to 2013, with evidence of continued acceleration. MMRs reduced consistently in south, east, and southeast Asia between 1990 and 2013, but maternal deaths increased in much of sub-Saharan Africa during the 1990s. 2070 (1290–2866) maternal deaths were related to HIV in 2013, 0·4% (0·2–0·6) of the global total. MMR was highest in the oldest age groups in both 1990 and 2013. In 2013, most deaths occurred intrapartum or postpartum. Causes varied by region and between 1990 and 2013. We recorded substantial variation in the MMR by country in 2013, from 956·8 (685·1–1262·8) in South Sudan to 2·4 (1·6–3·6) in Iceland.

Interpretation

Global rates of change suggest that only 16 countries will achieve the MDG 5 target by 2015. Accelerated reductions since the Millennium Declaration in 2000 coincide with increased development assistance for maternal, newborn, and child health. Setting of targets and associated interventions for after 2015 will need careful consideration of regions that are making slow progress, such as west and central Africa.

Funding

Bill & Melinda Gates Foundation.

Introduction

Since the 1980s, the global health community has focused on reducing maternal mortality through a sequence of initiatives, beginning with the Safe Motherhood movement in 1987, to the creation of the Partnership for Maternal, Newborn and Child Health in 2005.1, 2 The priority accorded to reductions in maternal mortality is shown by its choice as one of the eight Millennium Development Goals (MDGs). Despite these efforts and visibility, there was broad concern that little or no progress was being made, which prompted intensified efforts by the UN Secretary General through the launch of Every Woman Every Child in 2010, and the subsequent creation of the Commission on Information and Accountability for Women's and Children's Health.2, 3 In 2010, a comprehensive assessment of global trends in maternal mortality suggested that the maternal mortality ratio (MMR; number of maternal deaths per 100 000 livebirths) had decreased by 1·3% per year since 1990.4 Subsequent revisions of the historical estimates have shown even larger worldwide rates of change, from −1·9% to −3·1% per year.5, 6 This evidence collectively suggests that, although concerns about the rate of change of maternal mortality might have been too pessimistic, there is substantial uncertainty about how rapid the decrease has been and about the actual numbers of deaths in several large populations. If policy debates about acceleration of maternal mortality reductions are to be usefully informed, goals established, and targets set for reproductive health, up-to-date monitoring of the levels and trends in maternal mortality is essential.7

Compared with child mortality, maternal mortality has been more difficult to track over time at the national level.8 Several major challenges have to be addressed in any measurement effort: misclassification of maternal deaths to other causes in countries with complete vital registration and medical certification of causes of death; substantial sampling error in measurements that depend on survey recall because few maternal deaths are reported; large non-sampling error in survey and census measurements as demonstrated in settings with repeated overlapping measurements; variation in the demographic assessment of reproductive-age mortality from all causes, particularly in the 1990s; and the need for models to synthesise data from several studies or generate estimates when data are sparse.9, 10, 11 The substantial differences between global modelling efforts, which are at times substantial, emphasise the influence of each of the analytical steps used to estimate maternal mortality.12 Political attention to how countries are progressing towards MDG 5 targets is intensifying.1, 13 Donors, global health partners, and national programme managers are understandably frustrated by the wide uncertainty intervals and the variability of estimates from different analysts.8

Here, we use the systematic approach of the Global Burden of Diseases, Injuries, and Risk Factors Study 2013 (GBD 2013) to measure levels and track trends in maternal mortality, the key causes contributing to maternal death, and the timing of maternal deaths. In GBD 2013, with application of rigorous statistical methods to critically appraise and synthesise data from different sources to estimate levels and causes of death in each age and sex group, a consistent and holistic approach to the challenges of maternal mortality measurement is used that enables comparisons across time, country, and other important causes of death in women of reproductive age. Algorithms for cause of death reclassification are applied consistently across all causes and modelling strategies use methods with clearly quantified out-of-sample predictive validity.14 On the basis of recent trends in MMR, we also project an MMR scenario for 2030 to inform policy debates by identifying which countries are in greatest need of intensified focus.

Section snippets

Data

We used the GBD 2013 cause of death database, which extends from 1980 to 2013, to estimate maternal mortality. Although we report estimates for the MDG period 1990–2013, data for 1980–90 are included in the analysis to improve the robustness of the time trend estimation. Naghavi and colleagues15 provide substantial detail about the inclusion criteria and data processing of studies across all causes. Briefly, building on previous analyses, we identified data from 180 of 188 GBD countries,

Results

The total annual number of maternal deaths decreased from 376 034 (95% UI 343 483– 407 574) in 1990, to 292 982 (261 017–327 792) in 2013 (figure 3A, table 1). The reduction accelerated steadily from 1990 to 2013 (figure 3B), with corresponding decreases in MMR (table 1). Between 2003 and 2013, the annual rate of change in MMR was greater than −1%, reaching −3·3% for 2012–13 (figure 3B).

MMR was highest in the oldest age groups and lowest in women aged 20–29 years in both 1990 and 2013 (figure 4

Discussion

On the basis of recent data and a refined understanding of the association between HIV and maternal mortality, we have shown that worldwide maternal mortality has decreased by 1·3% per year since 1990. Despite reductions in the number of maternal deaths—from about 376 000 in 1990 to about 293 000 in 2013—only 16 countries, seven of which are developing countries, are expected to achieve the MDG 5 target of a 75% reduction in the MMR by 2015. We noted two different patterns in developing

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