Huang, R. S., Spence, A. R., & Abenhaim, H. A. (2025). Age-related disparities in national maternal mortality trends: A population-based study. PloS one, 20(1), e0316578. https://doi.org/10.1371/journal.pone.0316578
Huang RS, Spence AR, Abenhaim HA. Age-related disparities in national maternal mortality trends: A population-based study. PloS one. 2025;20(1):e0316578. doi:10.1371/journal.pone.0316578
Huang, R. S., et al. "Age-related disparities in national maternal mortality trends: A population-based study." PloS one, vol. 20, no. 1, 2025, pp. e0316578.
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RRM Academy Synopsis
US maternal death risk rises sharply with age after 35
A US national records study of births and deaths from 2000 to 2019 found maternal death risk rose steeply with age from 35 onward. Women 35 and older had about 32 out of 100 maternal deaths but about 15 out of 100 births. Maternal deaths per 100,000 births also rose over the two decades, most in women 35 and older.
Key Findings
Between 2000 and 2019, the US recorded 21,241 maternal deaths among 80,710,348 live births, an average of 26.3 maternal deaths per 100,000 births (95% CI 21.8–31.2).
Women aged 35 years or older accounted for 32.3% (n = 6,870) of maternal deaths and 15.1% (n = 12,218,318) of live births.
Compared with women aged 25–29, adjusted odds ratios for maternal death were 1.60 (1.53–1.67) at 35–39, 3.78 (3.60–3.99) at 40–44, 28.49 (26.49–30.65) at 45–49 and 343.50 (319.44–369.37) at 50–54.
The adjusted odds of maternal death rose each year (OR 1.07, 1.06–1.07), an annual increase of 1.6 per 100,000 births. The greatest annual increase was in women aged 50–54.
Non-obstetric causes accounted for 34.5% (n = 7,334) of maternal deaths. All top ten underlying causes in 2000 were obstetric; the 2019 top ten included accidental poisoning and assault.
Interpretation
A retrospective population-based study analyzes existing records. The authors used US birth and death certificate files covering all live births and all recorded maternal deaths from 2000 to 2019. They counted any death during pregnancy or within 42 days of its end, including accidental and incidental causes, so the definition is broader than the World Health Organization definition. Odds ratios across age groups were adjusted for year and race, and odds ratios for yearly change were adjusted for race. Women under 15 also had higher odds (adjusted OR 3.12, 2.38–4.10), based on 52 deaths. The authors note the records lack body mass index and mode of conception.
RRM Context
In their discussion of the higher risk at older ages, the authors point to chronic conditions that are more common with age, including hypertension and diabetes. They suggest that more assisted reproduction among women 35 and older may also have contributed. Restorative reproductive medicine evaluates the health of both partners and treats the cause.
Our editorial summary of this paper, not the article's abstract.
Abstract
Objective
An upward trend in maternal age has been observed in the United States (US) over the last twenty years. The study objective was to examine the association of maternal age with maternal mortality in the US and examine temporal trends in mortality by maternal age.
Methods
A retrospective population-based analysis in the US between 2000-2019 was conducted using records from the Centers for Disease Control and Prevention's "Mortality Multiple Cause" and "Birth Data" files. Annual incidence and period trends in maternal deaths were calculated using the annual maternal deaths over annual live births across age groups. Multivariate logistic regression models were used to estimate the association between maternal age and risk of maternal mortality and calculate temporal changes in risk of mortality over the study period.
Results
Between 2000-2019, 21,241 deaths were observed in women during pregnancy and childbirth for an average incidence of 26.3 maternal deaths/100,000 births (95% CI 21.8-31.2). Of all deaths, 6,870 (32.3%) were in women ≥35 years, while only 15.1% of live births were attributed to women ≥35 years. Compared with women 25-29 years of age, there was a significantly greater risk of maternal mortality among women 35-39 (OR 1.60, 1.53-1.67), 40-44 (3.78, 3.60-3.99), 45-49 (28.49, 26.49-30.65) and 50-54 (343.50, 319.44-369.37). Risk of mortality increased over time, with the greatest rise in women ≥35 years.
Conclusion
In the US, maternal mortality increased during the past two decades, especially in women ≥35 years. Given these findings, targeted strategies to reduce the increasing maternal mortality should become a priority.
