Trends in Pregnancy-Related Mortality in the United States: Pregnancy Mortality Surveillance System, 2005-2024

To describe Pregnancy Mortality Surveillance System (PMSS)-identified underlying causes of pregnancy-related deaths and changes over time in the overall and cause-specific pregnancy-related mortality ratios in the United States, 2005-2024.

For this descriptive study, all pregnancy-related deaths were identified in the Centers for Disease Control and Prevention's PMSS from 2005 to 2024. The PMSS has nine mutually exclusive underlying cause-of-death categories: hemorrhage, infection or sepsis, amniotic fluid embolism, thrombotic pulmonary or other embolisms, hypertensive disorders of pregnancy, anesthesia complications, cerebrovascular accidents, cardiovascular conditions (including cardiomyopathy), and other noncardiovascular medical conditions. Beginning with 2020 data, a new cause-of-death code specific for coronavirus disease 2019 (COVID-19) was added to the infection or sepsis category. Cause-specific proportionate mortality was calculated overall and in 5-year intervals. In addition, trends in pregnancy-related mortality ratios, overall and by underlying cause of death, were assessed over time with Joinpoint regression. Joinpoint analysis identified statistically significant changes in trends (joinpoints) and in annual percent change (APC) across distinct time periods.

During 2005-2024, 14,310 pregnancy-related deaths were identified in PMSS. There was a significant increase in the overall pregnancy-related mortality ratio from 2018 to 2021 (APC 20.11, P<.001) and a significant decrease from 2021 to 2024 (APC -17.91, P<.001). Throughout the study period, the most prevalent causes of death were infection or sepsis, cardiovascular conditions (including cardiomyopathy), other noncardiovascular medical conditions, and hemorrhage. Cardiovascular conditions were the leading cause of death for 17 of the 20 years. Trends in cause-specific pregnancy-related mortality ratios differed by cause of death. Deaths resulting from infection or sepsis had the largest increase in 2018-2021 (APC 86.17, P<.001) and the largest decrease in 2021-2024 (APC -49.67, P<.001), which coincided with the timing of the COVID-19 pandemic. Hemorrhage deaths showed an increasing pregnancy-related mortality ratio from 2017 to 2024 (APC 6.84, P=.02). The pregnancy-related mortality ratio for other cardiovascular conditions decreased from 2020 to 2024 (APC -9.49, P=.04).

From 2005 to 2024, the most prevalent causes of pregnancy-related death were cardiovascular conditions, infection or sepsis, other noncardiovascular medical conditions, and hemorrhage. However, cause-specific trends in pregnancy-related mortality in the United States have changed over time. These differences underscore the importance of sustained surveillance to better inform clinical and public health efforts to address leading and emerging causes of pregnancy-related death.