What are the impacts of the movement to Medicaid managed care on prenatal care and birth outcomes? The project was comprised of two distinct components. In the first component, researchers at the Urban Institute conducted case studies of two states (Texas and Missouri) regarding the implementation of 1115 or 1915(b) waivers that focus on pregnancy related services, to assess how managed care systems affect birth outcomes. They also characterized each Medicaid managed care plan and identified the type of managed care arrangement under which each pregnant woman was enrolled. In the second component, they built on a previous RWJF funded project and conducted a national cross-sectional time series analysis of natality data. Data came from the National Natality files, HCFA managed care reports, other Urban Institute surveys, secondary data files such as the Area Resource File, US Census data, and state natality and other data files. They also conducted substantial primary data collection, through case studies, and a survey of managed care plans in the two selected case study states. The objective of the study was to assess how the move to managed care under the Medicaid program affects birth outcomes.