Impact of State-Level Changes on Maternal Mortality: A Population-Based, Quasi-Experimental Study

Abstract

Introduction: Recent increases in maternal mortality and persistent disparities have led to speculation about why the U.S. has higher rates than most high-income countries. The aim was to examine the impact of changes in state-level factors plausibly linked to maternal mortality on overall rates and by race/ethnicity.

Methods: This quasi-experimental, population-based, difference-in-differences study used 2007-2015 National Vital Statistics System microdata mortality files from 38 states and DC. The primary exposures were 5 state-level sexual and reproductive health indicators and 6 health and economic conditions. Maternal mortality rate was defined as number of deaths of women while pregnant or within 42 days of termination of pregnancy per 100,000 live births. A difference-in-differences zero-inflated negative binomial regression model was estimated using the race/ethnicity-age-state-year population as the denominator and adjusting for race/ethnicity, age, state, and year. Data were analyzed in 2017-2018.

Results: There were 4,767 deaths among women up to age 44 years, resulting in a maternal mortality rate of 17.9. Reducing the proportion of Planned Parenthood clinics by 20% from the state-year mean increased the maternal mortality rate by 8% (incidence rate ratio, 1.08; 95% CI=1.04, 1.12). States that enacted legislation to restrict abortions based on gestational age increased the maternal mortality rate by 38% (incidence rate ratio, 1.38; 95% CI=1.03, 1.84). Planned Parenthood clinic closures negatively impacted all women, increasing mortality by 6%-15% across racial/ethnic groups, whereas gestational limits primarily increased mortality among white women.

Conclusions: Recent fiscal and legislative changes reducing women's access to family planning and reproductive health services have contributed to rising maternal mortality rates.