WASHINGTON — Maternal deaths due to obstetric causes declined after the pandemic, according to research presented at the American College of Obstetricians and Gynecologists (ACOG) 2026 Annual Meeting. 

The drop in obstetric deaths from 2021 to 2023 followed more than a decade of rising rates, Ji Hea Byun, MD, obstetrician at the Catholic University of Korea, Seoul, South Korea, told attendees. “The improvement is encouraging, but we should be careful in interpretation as this analysis describes the trend,” Byun said. “It does not tell us why the decline happened, so the drivers of the improvement need further study.”

The data represent only deaths in which the diagnosis code began with O in the month and a half after birth, thereby excluding deaths due to any other cause that was not explicitly attributed to an obstetric event.

Although maternal mortality has remained a major public health concern in the US, contemporary national trends through 2023, including trends by age, have not been well described, Byun told attendees. “Identifying high-risk age groups may help target prevention efforts,” she said.

The researchers analyzed national death certificate data that were linked to live-birth counts in the National Vital Statistics System. They looked specifically at US mothers aged 15-44 who died within 42 days of giving birth and whose death was coded as being tied to an obstetric cause. They calculated the maternal mortality ratio (MMR) — deaths per 100,000 live births — for each year from 2007 through 2023.

The MMR began at 16.8 in 2007 and peaked at 33.5 in 2021, but it has fallen since then to 19.6 in 2023. The three most common causes included hemorrhage, infection, and preeclampsia/hypertensive disorders. The data showed a sharp drop in the MMR in 2020, when it was 24.5. Byun said it was not possible from this data set to know the cause of that one-year drop during the first year of the pandemic. 

However, since maternal deaths coded with COVID were not included in the analysis, it is possible that maternal deaths attributed to COVID also were in women with concomitant pregnancy- or postpartum-related conditions that were not captured in the diagnosis codes because of the COVID diagnosis. For example, a woman who had a hypertensive disorder of pregnancy but whose death was coded as being due to COVID would not appear in these statistics. 

In line with other data, Black women had the highest MMR, with a peak of 69.9 per 100,000 live births in 2021 and still high at 50.3 in 2023. “The overall racial disparity persisted despite national improvement,” Byun reported. 

The Commonwealth Fund reported last year that pregnancy-related deaths nearly doubled between 2019 and 2021, but that measure included COVID deaths, which accounted for the substantial temporary increase.

The researchers only stratified the data by age and found the highest burden of maternal mortality by far occurred in those aged 40-44. Even at the most recent lower rate in 2023, the MMR in this age group was approximately 60 compared to less than 30 for all other age groups. Those aged 35-39 also had a modestly higher MMR than the other age groups of 30-34, 25-29, 20-24, and 15-19 years, which all clustered together. However, the rate fell from 2021 to 2023 across all age groups.

“The practical implication is that even with recent national improvement, older mothers remain an important high-risk group for continued surveillance and maternal safety efforts,” Byun said. “So clinically, this supports extra vigilance, readiness, and targeted prevention efforts for older pregnant patients.”

Notably, the data did not include deaths coded with anything other than obstetrics, so maternal deaths due to suicide, overdose, homicide, motor vehicle accidents, or other trauma were not included. In a study published in The New England Journal of Medicine in February, the leading cause of maternal death within 42 days of giving birth was unintentional drug overdose, followed by homicides and suicides. 

“I was surprised that maternal mortality by [Byun’s] metric was increasing, and I’m very impressed that it’s decreasing,” Ryan McDonald, MD, clinical professor of obstetrics and gynecology at the University of Wisconsin School of Medicine and Public Health in Madison, told Medscape Medical News.

“However, the biggest problem with this topic — not this particular research — is agreeing on a definition, so we can really understand what these statistics are doing. The change in the definition in terms of the timing of what’s maternal mortality and then what gets coded as maternal mortality limits this whole area of study.”

Maternal mortality can be defined as occurring within 42 days of giving birth or as occurring up to one year postpartum. In addition, some reports of maternal mortality rates are limited exclusively to obstetric causes as this one is, sometimes to any medical cause (including cardiovascular deaths not coded as obstetric), and sometimes inclusive of all deaths, including trauma, suicide, overdose, and homicide.

“I would argue that the biggest problem we have is that we need to agree on the term to study it rather than continually trying to interpret trends that are uninterpretable,” McDonald said.

Kurt Barnhart, MD, director of the Women’s Health Clinical Research Center at the University of Pennsylvania in Philadelphia, agreed.

Obstetricians generally focus on hemorrhage and thrombosis as causes of maternal death, he said, and while those are not insignificant, “if we keep the definition as such, we’re going to keep focusing on hemorrhage rather than what we can focus on to make a greater public health impact on things like mental health.” 

No external funding was noted for the study. Byun, Barnhart, and McDonald had no disclosures. 

Tara Haelle is a science/health journalist based in Dallas.