- New research challenges current CDC reporting about rising maternal death rates in the U.S., suggesting maternal mortality is stable and on par with other developed countries.
- The study authors claim a “pregnancy checkbox” introduced by the CDC in 2003 may have contributed to inaccurate pregnancy-related death tolls.
- Discrepancies around direct, indirect, incidental, and accidental deaths among pregnant people may have led to reporting errors, researchers say.
- The CDC disagrees with the study findings and stands by the accuracy of its data collection methods.
The ongoing maternal health crisis in the United States affects millions of women who do not have access to quality prenatal and postnatal care, particularly those who live in areas with restricted abortion access.
These disparities fuel rising maternal mortality rates that disproportionately affect women of color.
But, new research suggests that the number of maternal deaths in the past two decades may have been overestimated.
The study, published March 12 in the American Journal of Obstetrics & Gynecology, shows maternal mortality in the U.S. held steady and was on par with other developed countries.
The study data also indicate that maternal deaths from direct obstetric causes declined over the past 20 years.
Researchers say the 2003 inclusion of a pregnancy checkbox on death certificates, which showed whether a person was pregnant at or near their time of death, misrepresented the increase in the number of maternal deaths.
“Our study showed that maternal mortality rates were low and stable between 1999-2002 and 2018-2021, which is very different from the high rates and dramatic increases reported by the NVSS [National Vital Statistics System] in recent years,” lead author Dr. K.S. Joseph, PhD, a Professor in the Departments of Obstetrics and Gynaecology and the School of Population and Public Health, University of British Columbia and the Children’s and Women’s Hospital & Health Centre of British Columbia said in a news release.
“We found that exclusive reliance on the pregnancy checkbox on death certificates, without corroboration from the cause-of-death information, led to an overestimation of maternal mortality rates by the NVSS in 2018-2021.”
Maternal death rates lower than CDC estimates
The researchers found that maternal deaths in the U.S. were stable overall, averaging at just over 10 per 100,000 live births from 1999 to 2002, as well as from 2018 to 2021.
This conflicts with maternal mortality rates reported by the Centers for Disease Control and Prevention, which increased from 9.65 per 100,000 live births to 23.6 per 100,000 live births for the same time period, respectively.
These findings challenge upward trends that were previously reported by the National Vital Statistics System (NVSS), a division of the CDC.
The CDC’s 2021 maternal mortality report shows nearly a 40% increase in overall maternal deaths from 2020, with rates for non-Hispanic Black women 2.6 times higher than white women.
The CDC told Healthline the agency disagrees with the AJOG analysis.
“The methods used in the AJOG report are known to produce a substantial undercount of maternal mortality. That’s because there are maternal deaths occurring that would not otherwise be identified if the death certificate didn’t include a pregnancy checkbox,” a CDC spokesperson said.
“Capturing these otherwise unrecorded maternal deaths is critical to understanding the scope of maternal mortality in the United States and taking effective public health action to prevent these deaths. The recent report’s analysis does not address this, nor does it provide evidence of how large any potential overcount may be.”
How were new maternal death rates calculated?
Maternal deaths may occur during pregnancy, childbirth, or the postpartum period resulting from conditions directly related to pregnancy or conditions exacerbated by pregnancy and birth.
To find out whether current maternal death rates were accurate, researchers examined NCHS data from 1999 to 2021.
They examined factors that may have been driving the increase. These included:
- changes in obstetric factors
- maternal chronic conditions
- “surveillance issues” (i.e., changes in data collection methods)
They also focused on maternal deaths that included pregnancy among the causes of death on death certificates.
The researchers concluded deaths resulting from obstetric causes (i.e., preeclampsia or hemorrhaging) decreased over the time periods studied by the researchers.
Deaths resulting from indirect causes that were exacerbated by pregnancy (i.e., hypertension) increased, however.
On par with CDC reporting, non-Hispanic Black women had disproportionately high rates of maternal mortality due to complications including:
- ectopic pregnancy
- cardiovascular conditions
- kidney disease
- other diseases
The researchers determined the pregnancy checkbox was linked to higher rates of less specific and incidental causes of death.
“By not relying on the pregnancy checkbox, our approach avoided the misclassification that has given the false impression of increasing maternal mortality rates in the U.S., study co-author Dr. Justin S. Brandt, director of the Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, NYU Grossman School of Medicine, said in the release.
“Identifying maternal deaths by requiring mention of pregnancy among the multiple causes of death shows stable maternal mortality rates and declines in maternal deaths from direct obstetric causes.”
‘Pregnancy checkbox’ miscalculations
In 2003, NCHS recommended adding a “pregnancy checkbox” to death certificates in the U.S. to better account for deaths occurring from a pregnancy complication.
As states began implementing the checkbox from 2003–2017, the CDC saw the quality of the data improve, and the maternal mortality rate was more than double the previously reported rate.
In 2018, NCHS made changes in coding rules and reporting to improve the accuracy of maternal mortality data and resumed publishing national maternal mortality rates after a pause in reporting following the phased implementation of the pregnancy checkbox.
However, the pregnancy checkbox may have led to discrepancies around how a positive checkbox was interpreted and accounted for.
For example, a pregnant person who died from high blood pressure would get a positive checkbox on their death certificate. But this is not considered a maternal death, despite the fact that her condition may have been exacerbated by pregnancy.
Another example would be a pregnant person with cancer who paused chemotherapy during pregnancy but then died of cancer because she was not able to receive treatment. This person would get a positive pregnancy checkbox, despite the cause of death being cancer, not obstetric.
“Researchers involved with the new study say the pregnancy checkbox system still accounts for many non-maternal and incidental deaths (i.e., a car accident) as maternal deaths, which they say has contributed to the errors in CDC’s maternal death rate reporting,” the CDC told Healthline.
“That said, the AJOG report confirms a prior CDC analysis, which found that the pregnancy box is sometimes mistakenly checked on death certificates, which contributes to some overcounting.”
A maternal health crisis persists, regardless of the data
Despite any disagreement over how maternal deaths are reported, experts agree that unacceptable disparities in maternal healthcare persist, fueling a disproportionate number of maternal deaths among racial and ethnic minority groups.
Looking ahead, researchers of the present study say the checkbox system could be improved by requiring physicians to specify the cause of death related to pregnancy.
“Accurate assessment of the number and causes of maternal death is an important priority for countries and healthcare policymakers. Improving maternal mortality surveillance is key to formulating plans to improve maternal health,” Dr. Roberto Romero, Editor-in-Chief for Obstetrics of the American Journal of Obstetrics & Gynecology (AJOG), and Chief of the Pregnancy Research Branch of NICHD, NIH, said in a statement.
Anu Sharma, founder and CEO of Millie, told Healthline that mortality rates, in general, are a narrow representation of the maternal health crisis in the U.S.
“Regardless of whether or not this specific data has been miscalculated, we undoubtedly have high rates of maternal morbidity, with nearly 50,000 near misses a year, as well as high rates of c-sections, preterm births, NICU stays, and poor maternal mental health,” Sharma said.
“On top of that, racial disparities for Black birthing people are significant, as this study continues to affirm. 36% of all U.S. counties are designated maternity care deserts. As researchers, policymakers, and providers all know — reducing the U.S. maternal health crisis to methodology differences around how mortality calculations are done ignores the harsh reality of what mothers giving birth in the U.S. face today.”
Takeaway
A new study suggests that maternal mortality rates in the U.S. may be lower than previous CDC estimates due to the 2003 addition of a pregnancy checkbox on death certificates.
The CDC disagrees with how the study authors calculated maternal death rates and stands by the accuracy of the agency’s data reporting.
Regardless of whether maternal deaths are up, down, or stabilized, a maternal health crisis persists in the U.S. that must be addressed.
