Distance to an Abortion Provider and Its Association with the Abortion Rate: A Multistate Longitudinal Analysis.

Context: Although one in four U.S. women has an abortion in her lifetime, barriers to abortion persist, including distance to care. This study evaluates the association between distance to care and the abortion rate, adjusting for abortion demand.

Methods: Two analyses were conducted using a data set linking provider locations and 2000-2014 county-level abortion data for 18 states; data sources included the Census Bureau, state vital statistics offices and the Guttmacher Institute. First, a series of linear regression models were run, with and without adjustment for demographic covariates, modeling distance as both a continuous and a categorical variable. Then, an instrumental variable analysis was conducted in which being 30 or more miles from a large college-enrolled female population younger than age 25 was used as an instrument for distance to a provider. The outcome variable for all models was abortions per 1,000 women aged 25 or older. All models were adjusted for state, year and state-year interaction fixed effects.

Results: Increased distance to a provider was associated with a decreased abortion rate. Each additional mile to a provider was associated with a decrease of 0.011 in the abortion rate. Compared with being within 30 miles of a provider, being between 30 and 90 miles from a provider was associated with 0.80-1.46 fewer abortions per 1,000 women. In the instrumental variable analysis, being 30 or more miles from a provider was associated with 5.26 fewer abortions per 1,000 women.

Conclusions: Distance to a provider may present a barrier to abortion by preventing access to care. Therefore, policies that increase travel distances have potential for harm.