WHO, UNICEF, UNFPA, World Bank Group, and United Nations Population DivisionTrends in Maternal Mortality: 1990 to 2015Geneva: World Health Organization, 2015.

Reducing maternal mortality is one of the international community's top priorities, and both the Millennium Development Goals (MDGs) and the Sustainable Development Goals (SDGs) have specific targets for declines in the maternal mortality ratio (MMR). Assessing progress toward these goals requires accurate estimates of the MMR at the country level. These estimates are difficult to obtain because many countries still lack civil registration for capturing vital events data, and where such systems exist underreporting is common. Estimates from other sources (e.g., surveys) are subject to large sampling errors. Given these challenges, a Maternal Mortality Estimation Interagency Group with participation from WHO, UNICEF, UNFPA, World Bank, and UNPD collaborated with teams of consultants to generate internationally comparable MMR estimates. This report presents updated regional and country estimates for 1990–2015. The principal methodological innovation is the reliance on a Bayesian modeling approach that optimizes the use of diverse country-specific data sources and provides estimates of uncertainty. Globally, the MMR is estimated at 216 per 100,000 live births in 2015, with an 80 percent uncertainty interval from 207 to 249. This represents a decline of 44 percent from the 1990 MMR of 385. Over the 25-year period, the annual number of maternal deaths declined from approximately 532,000 to 303,000. This is a substantial reduction but falls short of the three-quarters target set in the MDGs in 1990. Maternal mortality varies widely among regions, with the highest rates in sub-Saharan Africa (546) and the lowest in the developed regions (12). As a result, developing regions account for 99 percent of maternal deaths worldwide. Findings are summarized in tables with regional-level estimates of the MMR (with uncertainty ranges) as well as other indicators such as the absolute number of maternal deaths and the lifetime risk of maternal death. Country estimates are provided in an Appendix. The report's updated estimates provide a solid basis for assessing progress made toward the MDG goal, and they are the baseline for future assessments of SDGs. The text focuses on the technical aspects of modeling levels and trends. There is little discussion of the deeper causes that drive trends and differentials or of the reasons why the global decline in MMR has fallen short of the target set in 2000. The full data base, country profiles, and model specifications are available online.