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

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.

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.

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.

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