Preterm and low birth weight are the leading causes of infant mortality and childhood disability. In the U.S. racial disparities in birth outcomes persist, and there is evidence that discrimination partially contributes to this disparity. Most of research on discrimination and birth outcomes relies on self-reported experiences of discrimination, and there have been few studies examining discrimination at the U.S. national level. Social contexts in which greater hostility towards minorities is manifested may cause psychological stress and increase risk of adverse birth outcomes. The scientific objective of this research plan is to develop a new county-level indicator of discriminatory attitudes from social media data as well as make use hate crimes data and measures of explicit and implicit racial bias to provide a detailed and nuanced investigation of the impact of discrimination on birth outcomes and racial/ethnic disparities in birth outcomes. Another strength of this research plan is the longitudinal study design with multiple years of data for both measures of discrimination and birth outcomes, which allows us to control for temporal trends and stable characteristics of the counties. Furthermore, the influence of discrimination on birth outcomes may begin prior to pregnancy. There is increasing recognition of maternal health prior to conception influencing fetal development and birth outcomes. The project will empirically evaluate whether place-level discrimination is associated with biomarkers of chronic stress among young women of child-bearing age. This research plan is complemented by a training plan that builds on the applicant’s background in epidemiology and biostatistics and includes new training in: 1) developing expertise in Big Data, 2) measurement of discrimination, and 3) stress physiology and birth outcomes. The combined research and training plan will prepare the applicant for a successful independent research career evaluating how discrimination impact minority health and health disparities.