Project Summary / Abstract There are striking urban/rural disparities in access to hospital-based obstetric care in the US, and the gap in access between urban and rural communities is growing. Access to hospital-based obstetric care is critical to health outcomes before, during, and after pregnancy. Rates of severe maternal morbidity and maternal mortality are rising in the US, particularly for mothers living in rural communities. We know little about whether lack of access to hospital-based obstetric care may play a role in adverse maternal outcomes in rural areas. This study has two goals. First, we estimate the effect of losing access to hospital-based obstetric care in rural U.S. counties on maternal health outcomes measured at the time of delivery, and test for disparities by race/ethnicity and by maternal education, using Vital Statistics birth certificate records from 2005-2018. Second, we estimate the magnitudes of policy- relevant factors affecting rural mothers’ health outcomes directly as well as indirectly through loss of access to obstetric care; these policy-relevant factors include the state’s ACA Medicaid expansion status, hospital characteristics, and local market characteristics. These findings are intended to provide new information on the health consequences of rural hospital and obstetric unit closures, and how public policies can be used to offset some of the impact.