The number of women dying from pregnancy-related causes has dropped by more than 35 percent in the past 30 years - from more than a half-million deaths annually in 1980 to about 343,000 in 2008, according to a new study by the Institute for Health Metrics and Evaluation (IHME) at the University of Washington and collaborators at the University of Queensland.
IHME's research shows that deaths have been declining at an annual rate of about 1.4 percent since 1990. Contrary to previous reports that have shown very little change in the maternal mortality ratio (MMR), the global MMR - the number of women dying for every 100,000 live births - declined from 422 in 1980 to 320 in 1990. It reached 251 in 2008 and is on pace for further declines.
Developing countries, in particular, have made substantial progress toward the Millennium Development Goal set in 2000 of reducing the MMR. Although only 23 countries are on track to achieve the target of lowering the MMR by 75 percent between 1990 and 2015, countries such as Egypt, China, Ecuador, and Bolivia have been achieving accelerated progress.
"These findings are very encouraging and quite surprising," said Dr. Christopher Murray, UW professor of global health, director of the Institute, and one of the report's co-authors. "There are still too many mothers dying worldwide, but now we have a greater reason for optimism than has generally been perceived."
The study, "Maternal mortality for 181 countries, 1980-2008: a systematic analysis of progress towards Millennium Development Goal 5," appears April 12 in the online-first edition of the Lancet.
Beginning in 2007, researchers analyzed vital registration data, censuses, surveys, and verbal autopsy studies and created new methodological tools to generate the most accurate estimates to date of maternal mortality for nearly every country.
Researchers found that progress in reducing maternal mortality has been slowed by the ongoing HIV epidemic. Nearly one out of every five maternal deaths - a total of 61,400 in 2008 - can be linked to HIV, and many of the countries with large populations affected by HIV have had the most difficulty reducing their maternal mortality ratio.
Nearly 80 percent of all maternal deaths are concentrated in 21 countries, and six countries account for more than half of all maternal deaths.
Eight low-income countries have seen annual increases in the MMR over the period 1990 to 2008, including Afghanistan and Zimbabwe, as have several high-income countries, such as the United States, Canada, and Norway.
At least part of the increase in high-income countries appears to be due to changes in the way maternal deaths are reported. Mothers in the United States now die at a higher rate than in most other high-income countries, four times the rate of Italy and three times the rate of Australia.
"As we gather more data, we will have a better sense of how much of the rise in maternal deaths can be traced to better reporting and how much may be due to other factors," said Margaret Hogan, an IHME researcher and the paper's lead author.
Maternal mortality is better documented than deaths from HIV, tuberculosis, and other causes, the researchers found. They intend to share the new methods they have created for estimating maternal mortality to help governments, development agencies, and aid organizations better understand trends in the MMR.
"If we can find out why a country such as Egypt has had such enormous success in driving down the number of women dying from pregnancy-related causes, we might be able to export that success to countries that have been lagging behind," said Dr. Murray.
IHME will further explore maternal mortality in IHME's upcoming report, "Building Momentum: Global Progress Toward Reducing Maternal and Child Mortality," to be published later this spring.