Abstract 135: Contribution Of Maternal Age To Trends In Pre-pregnancy Hypertension Prevalence In The United States From 1995-2019: A Kitagawa Decomposition Analysis

Abstract

Introduction: Prevalence of pre-pregnancy hypertension (HTN) has increased concurrently with maternal age in the US. We sought to understand the contribution of changes in maternal age vs. age-related HTN prevalence to trends in pre-pregnancy HTN. Methods: We included individuals aged 15-44 years old with a singleton first live birth in 1995-1999 and 2015-2019 from the National Vital Statistics System. We calculated the prevalence of pre-pregnancy HTN per 1,000 live births in 1995-1999 and 2015-2019, overall and in each 5-year age group. Using a Kitagawa analysis, we decomposed change in prevalence into two parts: (1) change in maternal age distribution and (2) change in age-specific prevalence of pre-pregnancy HTN (rate component). Analyses were repeated by self-identified race and ethnicity. Results: From 1995-1999 to 2015-2019, the proportion of first births decreased from 53% to 39% in 15-24 year olds and increased from 47% to 61% in 25-44 year olds. Pre-pregnancy HTN prevalence increased from 6.4 in 1995-1999 to 16.7 in 2015-2019 per 1,000 live births ( TABLE ). Changes in maternal age distribution and age-specific prevalence were associated with 16% and 84% of the increase in pre-pregnancy HTN, respectively. While prevalence differed by race and ethnicity, changes in age-specific prevalence accounted for the majority of changes in pre-pregnancy HTN in each group. Conclusions: Adverse trends in pre-pregnancy HTN were driven primarily by increasing age-specific prevalence overall, and in all race and ethnicity groups. Public health efforts are needed to identify and target the cardiovascular risk factors driving these age-specific trends and improve maternal health.