Medicaid insures an estimated 43% of all births in Michigan and provides additional funding for enhanced prenatal services (EPS). The objectives of this study are to report on the (1) use of statewide administrative data to examine risk characteristics and EPS enrollment of Medicaid-insured pregnant women in Michigan; and (2) presence and extent of a broad range of risk factors in a sample of EPS participants in Michigan, using a newly developed two-tier, risk screener and assessment tool. This study uses Vital Records, Medicaid and other data to describe EPS participation by maternal risks in the statewide population of Medicaid-insured pregnant women (54,582 in the fiscal year 2005). The screener study data is a convenience sample of 2,203 women screened between February 2005 and October 2007. The administrative data indicates that 26% of Medicaid-eligible pregnant women had EPS contact. Most women with health behavior risks, such as smoking and drug use, had no contact with EPS (68-72%). Approximately 58% of all Medicaid-insured women had zero to two co-occurring risks, while 42% had three or more of the analyzed risks. Among screened women who smoke, 9% smoked more than a pack a day. Approximately 34% of women with a depression screen scored in the moderately or severely depressed range. The results of this study suggest great opportunity for EPS enhancement by improving the capacity to identify and engage women with modifiable risks, match interventions to specific health problems, and deliver services at an intensity warranted by the risk level.