• Posted July 3, 2023

U.S. Maternal Mortality Rates Have More Than Doubled in Two Decades

The number of pregnant and postpartum women who die in the United States has more than doubled in two decades, hitting particular racial groups especially hard.

New research found sharp increases in maternal death rates between 1999 and 2019, especially among Black, American Indian and Alaskan Native women. Those who live in the South, the Mountain States and the Midwest were also at greater risk.

Researchers from the Institute for Health Metrics and Evaluation (IHME) at the University of Washington in Seattle and Mass General Brigham in Boston used government data on deaths and live births to study this, using computer modeling to create estimates of maternal deaths over the time periods.

"Maternal mortality is a crisis in the United States. These rates have been increasing over the past several decades and were exacerbated by the pandemic," said study author Dr. Allison Bryant, senior medical director for health equity at Mass General Brigham. "Our study sheds light on the wide disparities within maternal mortality rates -- the specter of maternal death differentially burdens some ethnic and racial populations."

Maternal deaths are those that happen during or up to one year after a pregnancy.

The U.S. Centers for Disease Control and Prevention lists common causes as mental health conditions such as suicide or substance use disorder-related overdose; excessive bleeding; cardiac and coronary conditions; infection; blood clots; cardiomyopathy (a disease of the heart muscle), and high blood pressure-related disorders.

"These disparities in maternal mortality are just the tip of the iceberg and tell us a lot about the health risks facing people in the states where these deaths are most likely to occur," said study co-author Dr. Greg Roth, director of the Program in Cardiovascular Health Metrics at IHME.

"In the U.S., maternal deaths are often caused by vascular diseases like severe high blood pressure or blood clots. So, maternal deaths share many of the same drivers as heart attacks, strokes and heart failure," Roth said in a news release from both universities. "Our state-by-state research emphasizes where we need to focus our prevention efforts and which groups are suffering the most."

While maternal deaths doubled over the 20 years for all racial and ethnic groups, they rose most substantially for American Indian and Alaskan Native women. But Black women still had the highest rates of any group. The average of state-level rates began to plateau for Black women before the pandemic, around 2015.

"The bottom line is that in the U.S. we have a pretty fractured health care system around maternal and women's health. And ultimately, any failed system affects those that are most vulnerable and most marginalized, right?" Dr. Laurie Zephyrin, senior vice president of advancing health equity at the Commonwealth Fund, told HealthDay recently.

Bryant noted that factors like structural racism and interpersonal racism worsen these disparities.

Southern women had high maternal deaths across all racial and ethnic groups, but Black women were hit the hardest, the study found. Black women also had the highest rates in some states in the Northeast, which tripled over the 20 years.

"Often, states in the South are called out as having the worst maternal mortality rates in the nation, whereas California and Massachusetts have the best. But that doesn't tell the whole story," Bryant said in the release. "It's essential to look at the disparities between populations that exist even in the 'best' states."

The study, funded by the U.S. National Heart, Lung, and Blood Institute, the U.S. National Institutes of Health and Gates Ventures LLC, was published July 3 in the Journal of the American Medical Association.

Study limitations include that researchers didn't always have access to information about the causes of maternal death. Recording of maternal deaths on death certificates also changed over the study period.

National data on maternal deaths show they increased further in 2020 and 2021, when the pandemic made it harder to access health care and slowed prevention efforts. The pandemic may have widened the disparities seen in this study, Bryant said.

“Our findings provide important insights on maternal mortality rates leading up to the pandemic, and it's likely that we'll see a continued increase in the risk of maternal mortality across all populations if we analyze data from subsequent years,” Bryant said. “Black individuals would likely still have the highest rate, but there may be a higher uptick in some of the other groups in the last few years. As we emerge from the pandemic, we must renew our focus on addressing maternal mortality.”

More information

The Office on Women's Health has more on pregnancy.

SOURCE: Institute for Health Metrics and Evaluation/Mass General Brigham, news release, July 3, 2023