Medicaid Enrollment and Outcomes Over the Reproductive Lifecourse - PROJECT SUMMARY/ABSTRACT The prevalence of chronic diseases such as diabetes, depression, and hypertension is increasing among young adults. If not properly managed in the preconception period, these conditions may contribute to worsening birth outcomes. However, early adults aged 19 – 34 years have the highest uninsurance rates in the US, and experience high rates of insurance status changes, sometimes called churn. Churn is associated with poor control of chronic conditions, low continuity of care, low self-rated health, and low prenatal care receipt. Uninsurance and churn in early adulthood limit access to health care during a critical time to improve pregnancy outcomes. Because Medicaid is relatively generous during pregnancy, it provides coverage for 40% of US births, including 90% for those who experience pregnancy-related churn. This grant will fill knowledge gaps about the relationship between preconception Medicaid enrollment and pregnancy outcomes. We will do so by leveraging two features of Medicaid policy. First, starting in 2014, the Medicaid expansion encouraged states to increase income thresholds for adult Medicaid eligibility, and was associated with increased coverage during early adulthood. State variation in adoption of Medicaid expansion allows comparison of otherwise similar individuals in Medicaid expansion states and non-expansion states to test whether increased coverage improved outcomes. Second, as in pregnancy, childhood Medicaid coverage is relatively generous, covering 40% of youth 18 years and younger. We will therefore use pediatric Medicaid claims to build and characterize of a cohort of individuals who grew up in low-income households. This will limit confounding by indication and will focus our analysis on individuals likely to be low-income in early adulthood, and thus most likely to benefit from the Medicaid expansion and to have observable Medicaid-insured births. Aim 1 will define patterns of Medicaid coverage in early adulthood and test whether these patterns are associated with state adoption of the Medicaid expansion. Aim 2 will test whether residence in a state that adopted the Medicaid expansion is associated with pregnancy outcomes for early adult women. We will use Medicaid claims from 17 – 18 year- olds with female sex to identify individuals likely to be low income in adulthood. We will define patterns of Medicaid coverage in early adulthood (through approximately age 25). We will test hypotheses using near-far matching and a differences-in-differences approach. This project innovates by conceptualizing Medicaid coverage over an extended preconception period, rather than in association with individual pregnancies, consistent with mechanisms through which long-term management of risk factors, including chronic disease, can most influence pregnancy outcomes. Findings will provide evidence to inform changes in Medicaid policy and systems of care to improve preconception health, aligning with NICHD's strategic plan to improve pregnancy outcomes, specifically Theme 3: Setting the foundation for healthy pregnancies and lifelong wellness and elucidating the role of the health care system in improving outcomes.