Moving to mandatory Medicaid managed care in Ohio: impacts on pregnant women and infants.

Background: Understanding the impacts of Medicaid managed care on pregnant women is critical because Medicaid covers more than a third of all births nationally, many under managed care arrangements.

Objectives: We sought to examine the impacts of mandatory Health Maintenance Organization (HMO) enrollment on prenatal care use, smoking, and birth weight for Medicaid-covered pregnant women in Ohio.

Research Design: Impact estimates are derived from a pre-post design with a comparison group, using Ohio birth certificate data linked to Medicaid enrollment files. Between April 1993 and April 1995 is the baseline period and October 1997 to June 1998 is the post-period. The treatment group consists of deliveries in 6 counties that implemented mandatory HMO enrollment in the mid 1990s; the comparison group consists of deliveries in 4 counties with voluntary HMO enrollment.

Subjects: Medicaid-covered deliveries to 24,799 non-Hispanic white women with no college education living in Ohio.

Measures: Seven outcomes are analyzed: first trimester care; last trimester or no care; adequate prenatal care; inadequate prenatal care; smoking during pregnancy; and birth weight.

Results: Our findings indicate that mandatory HMO enrollment in Ohio's Medicaid program had positive effects on prenatal care and led to reductions in maternal smoking. No effects were found on birth weight.

Conclusions: Even with the improvements related to Medicaid managed care, rates of inadequate prenatal care and maternal smoking remain relatively high. Addressing the underlying risk factors that are facing poor women and further expanding public programs may be critical to achieving further progress.