In 2016, only 13 states allowed pregnant women to access prenatal care regardless of their immigration status through either a state-funded program or the Children’s Health Insurance Program. As a result, many immigrant women do not have access to preconception care, prenatal care, or both. Perinatal epidemiologist Teresa Janevic and colleagues will estimate the effect of exclusion from preconception and prenatal Medicaid coverage on immigrant women’s access to prenatal care and adverse pregnancy events. Their mixed-methods approach combines qualitative interviews with state maternal and child health program administrative and natality data for 2011-2017. The project has two aims: 1) to test if immigrant women in Medicaid expansion states who were excluded from increased non-pregnancy Medicaid coverage experienced lower than expected improvements in prenatal care utilization and birth outcomes (preterm birth, low birth weight); and 2) to refine measures of state-level immigrant pregnancy policy through key informant interviews and identify mechanisms affecting immigrant birth outcomes. They will use a triple-differences approach to compare outcomes among foreign-born women before and after Medicaid expansion, with U.S. born co-ethnic women as a comparison group in states that extended coverage to immigrant women and those that do not. They will conduct interviews with state maternal and child health policy experts and obtain implementation information on state-level policy toward immigrants. Using a snowball sample approach, the PIs will conduct five to ten telephone interviews per state. They will select states that vary in terms of their implementation of the Medicaid expansion and their degree of immigrant inclusion.