March 13, 2024 -- Rates of maternal mortality in the United States are lower than previous estimates – yet still higher than other developed countries, according to a study published today.
Researchers said inaccurate recordkeeping has created undue alarm that the number of women who die while pregnant or soon after giving birth is rising. The maternal mortality rate is stable, they report, and deaths due to complications have dropped.
"Obstetric complications as a cause of death have decreased over time. That is expected because we have improvements in medical care," said K.S. Joseph, MD, PhD, an obstetrician and gynecologist at the British Columbia Children's and Women's Hospital and Health Centre in Vancouver, and a coauthor of the new study.
This good news comes with sobering asterisks. The maternal mortality rate in this country is still the highest in the developed world, and Black women in the United States are far more likely to die during or after pregnancy than women in other racial or ethnic groups.
"Anytime we have disparities, it's always going to boil down to two things: Implicit bias and systemic racism," said Veronica Gillispie-Bell, MD, section head for obstetrics and gynecology at Ochsner Health in Kenner, LA.
Gillispie-Bell said systemic racism results in economic insecurity and poor access to health care, which can lead to elevated maternal mortality among Black women. And implicit bias may cause different and potentially distressing treatment of Black women by doctors unaware they are doing it , she added.
Different Counting Method, Different Results
In 2003, officials of the National Center for Health Statistics recommended that a "pregnancy checkbox" be added to US death certificates, to address what was then considered an undercounting of deaths from a pregnancy complication. This checkbox identifies whether deceased women had been pregnant at the time of death, within 42 days of death, within 43 days to a year before death, not pregnant, or if the information was unknown.
Just because someone was pregnant when they died doesn't mean the pregnancy was to blame. But as Joseph and colleagues reported, the guidelines counted as a "maternal death" any death of a woman listed as pregnant on the certificate. From 2003 to 2017, this classification was true regardless of the person's age at death; since 2018, it has only been for women who died in childbearing years (age, 15-44).
The NCHS made this change to reduce the number of deaths that were wrongly attributed to pregnancy, Joseph said.
The checkbox method led to a purported 144% rise in maternal mortality in women aged 15-44, between 1999 and 2002 (9.65 of 100,000 live births) and 2018 and 2021 (23.6 of 100,000 live births).
Joseph and colleagues also looked for death certificates that mentioned an explicit cause of death, plus the fact of pregnancy. For these deaths to be linked to a pregnancy, they had to have been linked to an obstetric complication that occurred during pregnancy or by an underlying disease or condition the pregnancy worsened.
Using this refinement, the researchers identified 10.2 maternal deaths per 100,000 births from 1999 to 2002 and 10.4 maternal deaths per 100,000 births from 2018 to 2021. Deaths strictly related to pregnancy or delivery decreased. Indirect causes of maternal death such as cardiomyopathy (any disorder that affects the heart muscle), high blood pressure, or having a placenta stuck to the wall of the uterus increased.
For Black women, the alternative method showed 25.7 deaths per 100,000 births from 1999 to 2002 and 23.8 deaths per 100,000 births from 2018 to 2021. Both figures are double the overall rates, and Black women were also more likely to experience conditions like high blood pressure and cardiomyopathy, according to the researchers.
Gillispie-Bell is the medical director of Louisiana's Pregnancy-Associated Mortality Review Board, which sifts through mortality records to glean accurate maternal mortality statistics for the state.
And that process also shows disparities in maternal mortality between Black women and other US women, Gillispie-Bell said.
One strategy to address the gap, which both Joseph and Gillispie-Bell supported, is to intensively treat all signs of high blood pressure and cardiomyopathy in pregnant Black women as soon as they appear. Gillispie-Bell also suggested that clinicians take the Implicit Association Test to learn if they are unwittingly bringing bias into their interactions with Black women, so they can change their behavior if needed.
"Our brains take shortcuts to process information," Gillispie-Bell said. "This is how biases happen. It's not anything for anybody to feel guilty about."
