Understanding Global Trends in Maternal Mortality
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Understanding Global Trends in Maternal Mortality By Sarah Zureick- CONTEXT: Despite the fact that most maternal deaths are preventable, maternal mortality remains high in many Brown, Holly developing countries. Target A of Millennium Development Goal (MDG) 5 calls for a three-quarters reduction in the Newby, Doris maternal mortality ratio (MMR) between 1990 and 2015. Chou, Nobuko Mizoguchi, Lale METHODS: We derived estimates of maternal mortality for 172 countries over the period 1990–2008. Trends in Say, Emi Suzuki maternal mortality were estimated either directly from vital registration data or from a hierarchical or multilevel and John Wilmoth model, depending on the data available for a particular country. RESULTS: The annual number of maternal deaths worldwide declined by 34% between 1990 and 2008, from ap- Sarah Zureick-Brown proximately 546,000 to 358,000 deaths. The estimated MMR for the world as a whole also declined by 34% over this is postdoctoral fellow, Emory University; period, falling from 400 to 260 maternal deaths per 100,000 live births. Between 1990 and 2008, the majority of the Holly Newby is senior global burden of maternal deaths shifted from Asia to Sub-Saharan Africa. Differential trends in fertility, the HIV/ adviser, United AIDS epidemic and access to reproductive health are associated with the shift in the burden of maternal deaths Nations Children’s from Asia to Sub-Saharan Africa. Fund; Doris Chou is medical officer and Lale Say is coordina- CONCLUSIONS: Although the estimated annual rate of decline in the global MMR in 1990–2008 (2.3%) fell short of tor, World Health the level needed to meet the MDG 5 target, it was much faster than had been thought previously. Targeted efforts Organization; Nobuko to improve access to quality maternal health care, as well as efforts to decrease unintended pregnancies through Mizoguchi is research family planning, are necessary to further reduce the global burden of maternal mortality. associate, Univer- International Perspectives on Sexual and Reproductive Health, 2013, 39(1):32–41, doi: 10.1363/3903213 sity of Colorado, Boulder; Emi Suzuki is demographer, The World Bank; and John Maternal mortality is a key indicator of international de- In September 2000, the UN General Assembly adopted Wilmoth is professor, velopment, and its reduction has long been a challenge the United Nations Millennium Declaration. The follow- University of in low-income countries, despite the existence of effective ing year, the Millennium Development Goals (MDGs) California, Berkeley. interventions. The focus on maternal mortality as an im- were articulated. MDG 5 called for a three-quarters reduc- portant development measure dates back at least to the tion between 1990 and 2015 in the maternal mortality ra- 1980s, when researchers first highlighted the role of com- tio (MMR), the number of maternal deaths per 100,000 plications related to pregnancy and childbirth in death live births.6 At the same time, it was acknowledged that it rates among women of reproductive age and noted the would be difficult to track progress toward achieving this inadequacy of attention paid to addressing these largely target, since reliable data were lacking in the very countries preventable deaths.1–3 Also, in the mid-1980s, the World thought to have the greatest burden. A second target of Health Organization (WHO) estimated that approximate- achieving universal access to reproductive health by 2015 ly half a million women died yearly from maternal causes.4 was added in the subsequent reformulation of the MDGs.7 The 1987 Safe Motherhood Conference in Nairobi, It has been challenging for many countries to produce which was the first of a series of international meetings timely and accurate data on levels of maternal mortality that highlighted the worldwide problem of maternal mor- that would indicate the extent of their progress in reduc- tality, called for reducing maternal mortality in developing ing maternal deaths. To address the gap in data availabil- countries by half in one decade. Strategies for achieving ity on maternal mortality, WHO and the United Nations this goal included making family planning universally Children’s Fund (UNICEF) published, in 1996, the first available, providing prenatal care and trained assistance interagency estimates of maternal mortality, including at delivery, and ensuring access to emergency obstetric MMRs, numbers of maternal deaths and lifetime risks of care.5 Subsequent international conferences in the 1990s, death. The estimates, which referred to the year 1990, cov- including the World Summit for Children in 1990, the In- ered 174 countries. Of these countries, 77 had no direct ternational Conference on Population and Development or indirect estimates of maternal mortality, and their es- in 1994, and the Fourth World Conference on Women in timates were derived entirely from a statistical model. An 1995, also called for a substantial reduction in maternal additional 14 countries lacked data for predictor variables mortality. and thus had no estimate provided. 32 International Perspectives on Sexual and Reproductive Health Subsequent rounds of interagency estimates were pro- of maternal deaths, we generally adjusted data upward. duced for the years 1995, 2000 and 2005 with the collabo- This type of adjustment is needed, for example, to ac- ration of additional UN agencies. Each round of estimates count for maternal deaths related to abortion that are not built on previous rounds but introduced improvements reported or maternal deaths (especially those occurring in and innovations; thus, the estimates from the various early pregnancy) that are misclassified because pregnancy rounds were not strictly comparable. In September 2010, status is not known. an interagency exercise by WHO, UNICEF, the United Na- We adjusted downward any observations that reflected tions Population Fund (UNFPA) and the World Bank, led deaths during pregnancy, or the period following a preg- by an academic team at the University of California, Berke- nancy, that were not true maternal deaths. We defined a ley, produced trend estimates of the MMR and numbers maternal death as “the death of a woman while pregnant of maternal deaths for the years 1990, 1995, 2000, 2005 or within 42 days of termination of pregnancy, irrespective and 2008, overriding the previously reported findings.8 of the duration and site of the pregnancy, from any cause For the 2008 estimates, just 24 out of 172 countries lacked related to or aggravated by the pregnancy or its manage- national-level data on maternal mortality, a major improve- ment but not from accidental or incidental causes.”11 Ma- ment since the first UN interagency exercise. ternal deaths can be further classified into direct maternal In this article, we describe briefly the data and meth- deaths (deaths due to obstetric complications related to ods used to produce the most recent estimates released pregnancy) and indirect maternal deaths (deaths due to by the UN interagency team. We then highlight the results other diseases or conditions that have been aggravated by of this exercise, focusing on global, regional and country- pregnancy). specific trends observed over the period 1990–2008. Us- Maternal mortality and HIV/AIDS are two of the lead- ing the new estimates, as well as complementary data from ing causes of death among women of reproductive age other reports on progress toward the MDGs, we attempt worldwide, and there is evidence that HIV-positive women to understand better the factors contributing to the global are at higher risk than women who are not HIV positive progress in reducing maternal mortality observed over this for dying of complications related to pregnancy and child- period, as well as continued regional disparities in mater- birth.12 We sought to distinguish between AIDS-related nal mortality. deaths among pregnant women that were incidental to the pregnancy (i.e., would have occurred in the absence of a DATA AND METHODS pregnancy) and deaths that were caused primarily by HIV Various methods are available for collecting data on ma- infection, but in which pregnancy was a substantial aggra- ternal mortality, including vital registration, household vating factor. We refer to the latter category, classified as in- surveys (e.g., those that record recent household deaths direct maternal deaths according to the ICD-10 protocols or all deaths among respondents’ sisters—the “sisterhood (code O98.7), as AIDS-related maternal deaths.13 method”), surveillance systems, reproductive-age mortal- In sum, we divided all deaths that occurred during ity studies and censuses. Also, there are various measures pregnancy or within 42 days of termination of pregnancy of maternal mortality, including the maternal mortality ra- into the following categories: non–AIDS-related maternal tio (MMR), the maternal mortality rate, the adult lifetime deaths, AIDS-related maternal deaths, accidental or inci- risk of maternal mortality and the proportion of all deaths dental deaths not related to AIDS, and deaths related to among women aged 15–49 that are maternal deaths.9 AIDS that were not aggravated by pregnancy. Only deaths Data on maternal mortality are generally collected at the in the first and second categories are represented in our national level and disseminated by national statistical of- results. Separating AIDS-related and non–AIDS-related ma- fices. To produce global estimates, WHO maintains a ternal deaths gives us a sense of the impact of the