Public health researchers untangle two decades of maternal mortality data and finds that while early increases were driven by reporting changes, real increases followed during the COVID-19 pandemic.
PROVIDENCE, R.I. [Brown University] - A new study says much of the rise in U.S. maternal deaths before the COVID-19 pandemic may have been due to how deaths were recorded and did not reflect a true increase in risk. Yet when the COVID-19 pandemic hit, maternal death rates spiked across nearly every age and racial group.
The findings were detailed in a study in JAMA Pediatrics by a team of researchers at the Brown University School of Public Health, the University of Oxford and Columbia University. The findings challenge the assumption that maternal mortality has risen steadily in the U.S. over the last two decades.
The analysis, which was supported by funding from the National Institutes of Health and Britain's Engineering and Physical Sciences Research Council, looked at national maternal mortality data from the U.S. Centers for Disease Control and Prevention 2000 to 2023 and focused on the impact of a change made to death certificates: the addition of a checkbox that asked whether the person who died was pregnant. National rollout of the checkbox started in the early 2000s, giving researchers a way to compare numbers before and after it was added.
"We wanted to understand the trends in maternal, fetal and infant deaths in the U.S., but that turned out to be tricky because this checkbox was rolled out gradually," said Alyssa Bilinski, a co-author on the study and an assistant professor of health services, policy and practice and of biostatistics at Brown. "Around this time, we observed an increase in maternal deaths.
This led some experts to think the checkbox was catching more cases but also flagging some deaths that weren't actually related to pregnancy, Bilinski explained.
"The gradual rollout of the checkbox helped us to study its impact as a kind of quasi-experiment," Bilinski said. "Doing that, we could see that the very large proportion of the observed increase was due to the checkbox."
That steady rate changed dramatically at the height of the COVID-19 pandemic. In 2021, the adjusted rate of maternal deaths nearly doubled, reaching 18.9 deaths for every 100,000 live births. For the previous two decades, the adjusted rates hovered between 6.8 and 10.2 deaths per 100,000 live births.
Geographically, the South saw the largest regional increase in maternal deaths during the pandemic, while the Northeast was the only region where the change was not statistically significant.
Researchers linked the spike to pandemic-related disruptions in prenatal and postpartum care, greater exposure to infection and pre-existing inequities in the health care system. Maternal mortality rates declined again in 2022 to pre-pandemic levels.
"We started this study by asking what we assumed was a simple question: Has the number of pregnant women who die each year in the United States gone up or down since the year 2000?" said study the study's senior author Seth Flaxman of the University of Oxford. "As is so often the case in public health, the numbers do not speak for themselves. At the height of the COVID-19 pandemic, pregnant women died at significantly higher rates than they did before the pandemic. But when we took a careful look at the two decades before the pandemic, we found remarkably little change: in 2019 and 2023, pregnant women died at roughly the same rates as they did a generation earlier."
The findings highlight the importance of accurately tracking maternal health data, the researchers concluded. The results come at a time when massive job and funding cuts at federal health agencies have impacted researchers who study maternal mortality.
"Our results underscore the importance of investing in systems that systematically collect and rigorously analyze maternal and infant health data to inform policy," Bilinski said. "They also suggest additional questions, particularly about how best to reduce significant racial disparities in poor outcomes and how to best understand the comparability of U.S. metrics to peer countries."
For instance, the study confirmed longstanding racial disparities in maternal outcomes. Across all time periods studied, Black women consistently experienced maternal death rates about three to four times higher than those of white women.
The study also examined trends in infant and fetal mortality. Throughout the study period, the highest infant mortality rates were among Black infants. The researchers warned that this is a persistent and troubling pattern.
The researchers plan to continue studying how reporting changes around maternal mortality may have affected different groups of people and how maternal health trends are changing with shifts in reproductive care in the U.S.
"Although our findings suggest some reasons for optimism, we must continue to dedicate effort and resources to ensure that all Americans have the support they need for safe and healthy pregnancies," Bilinski said.
