Trends in Maternal, Fetal, and Infant Mortality in the US, 2000-2023.

IMPORTANCE

Accurately measuring maternal mortality trends has been challenging due to changes in data collection. This work disambiguates trends from the effects of introducing the pregnancy checkbox on death certificates and also analyzes closely related fetal and infant mortality.

OBJECTIVE

To describe trends in maternal, fetal, and infant deaths since 2000, including the impact of the COVID-19 pandemic.

DESIGN, SETTING, AND PARTICIPANTS: A national, population-level, epidemiological, cross-sectional analysis during 2000 to 2023 was conducted as well as a staggered difference-in-differences analysis on the pregnancy checkbox, using the US Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research (WONDER) database on underlying causes of death in the US to identify maternal, infant, and fetal deaths. Study population was restricted to mothers aged 15 to 44 years for all definitions of maternal mortality.

EXPOSURES

Staggered introduction of the pregnancy checkbox on death certificates across different states.

MAIN OUTCOMES AND MEASURES

Longitudinal study (2000-2023) reporting crude rates per 100 000 population for adjusted maternal mortality and per 1000 population for fetal and infant mortality at the national level and by US Census Bureau-designated main census regions, age groups, and race and ethnicity. Staggered difference-in-differences counterfactuals (1999-2023) on impact of pregnancy checkbox.

RESULTS

The introduction of the pregnancy checkbox was associated with 6.78 (95% CI, 1.47-12.09) deaths per 100 000 live births increase in reported maternal mortality, 66% (95% CI, 14%-117%) of the total increase from 2000 to 2019, with a smaller impact on maternal mortality excluding cause unspecified (adjusted maternal death rates). Adjusted maternal death rates remained consistently between 6.75 (95% CI, 5.97-7.61) to 10.24 (95% CI, 9.22-11.34) per 100 000 live births from 2000 until 2021, when it peaked at 18.86 (95% CI, 17.48-20.32); the rate dropped to 10.23 (95% CI, 9.22-11.32) in 2022. The death rates of Native American or Alaska Native women increased the most during the COVID-19 period, almost tripling from 2011 to 2019 (10.70 per 100 000 live births; 95% CI, 7.64-14.57) to the 2020 to 2022 period (27.47 per 100 000 live births; 95% CI, 18.39-39.45). The death rates of non-Hispanic Black women were highest across time-approximately triple the rate of non-Hispanic White women in each time period. Infant death rates per 1000 live births dropped from 6.93 (95% CI, 6.85-7.01) in 2000 to 5.44 (95% CI, 5.36-5.51) in 2020, increasing slightly to 2018 levels in 2021 to 2023. Fetal death rates per 1000 live births decreased from 6.28 (95% CI, 6.16-6.31) in 2005 to 5.53 (95% CI, 5.45-5.60) in 2022.

CONCLUSION AND RELEVANCE

Using difference-in-differences analyses, results of this study reveal that the pregnancy checkbox explained much of the observed increase in maternal mortality before the COVID-19 pandemic. Nevertheless, results of this cross-sectional study suggest that, even adjusting for pregnancy checkbox effects, most groups saw increases from 2011 to 2019 to the 2020 to 2022 period, indicating that the COVID-19 pandemic led to worse outcomes. The findings demonstrate the relevance of public health emergencies to maternal health outcomes.