Temporal Trends in Adverse Pregnancy Outcomes in Birthing Individuals Aged 15 to 44 Years in the United States, 2007 to 2019

Background Adverse pregnancy outcomes (APOs) (hypertensive disorders of pregnancy [HDP], preterm delivery [PTD], or low birth weight [LBW]) are associated adverse maternal and offspring cardiovascular outcomes. Therefore, we sought to describe nationwide temporal trends in the burden of each APO (HDP, PTD, LBW) from 2007 to 2019 to inform strategies to optimize maternal and offspring health outcomes. Methods and Results We performed a serial cross-sectional analysis of APO subtypes (HDP, PTD, LBW) from 2007 to 2019. We included maternal data from all live births that occurred in the United States using the National Center for Health Statistics Natality Files. We quantified age-standardized and age-specific rates of APOs per 1000 live births and their respective mean annual percentage change. All analyses were stratified by self-report of maternal race and ethnicity. Among 51 685 525 live births included, 15% were to non-Hispanic Black individuals, 24% Hispanic individuals, and 6% Asian individuals. Between 2007 and 2019, age standardized HDP rates approximately doubled, from 38.4 (38.2-38.6) to 77.8 (77.5-78.1) per 1000 live births. A significant inflection point was observed in 2014, with an acceleration in the rate of increase of HDP from 2007 to 2014 (+4.1% per year [3.6-4.7]) to 2014 to 2019 (+9.1% per year [8.1-10.1]). Rates of PTD and LBW increased significantly when co-occurring in the same pregnancy with HDP. Absolute rates of APOs were higher in non-Hispanic Black individuals and in older age groups. However, similar relative increases were seen across all age,racial and ethnic groups. Conclusions In aggregate, APOs now complicate nearly 1 in 5 live births. Incidence of HDP has increased significantly between 2007 and 2019 and contributed to the reversal of favorable trends in PTD and LBW. Similar patterns were observed in all age groups, suggesting that increasing maternal age at pregnancy does not account for these trends. Black-White disparities persisted throughout the study period.