Implementation of mandatory Medicaid managed care in Missouri: impacts for pregnant women.

Objectives: To assess the impact of mandatory Medicaid managed care in Missouri on prenatal care, maternal behavior, and low birth weight among pregnant women enrolled in Medicaid.

Study Design: Pre-post design using a comparison group with birth certificate and Medicaid enrollment data in 1995 and 2000.

Methods: Pregnant women delivering in 38 counties that implemented managed care in Medicaid were compared preimplementation and postimplementation with pregnant women delivering under Medicaid in 78 counties that remained fee-for-service (FFS) for separate samples of white (37,561) and black (13,640) non-Hispanic women. We calculated difference-in-difference estimates using linear probability regression models that controlled for maternal characteristics and time-invariant county differences. Analyses were stratified based on Medicaid enrollment before and after conception, managed care region, and marital status.

Results: Both managed care and FFS counties showed large improvements in prenatal care measures over time for both white and black women. Managed care was associated with a smaller percentage point increase relative to FFS counties in adequate care among whites of 1.9 and among blacks of 8.5, and a larger decrease in smoking of 4.8 and in Women, Infants, and Children Program enrollment of 2.3 among white women. No pattern across managed care regions was found with respect to timing of implementation. Smaller effects were evident among black and single women.

Conclusions: Although women experienced significant improvements statewide in prenatal care under Medicaid, improvements were smaller for managed care counties. Managed care may have a positive impact on smoking cessation, but other policy changes may be needed to improve birth outcomes.