Medicaid patients' access to office-based obstetricians.

Recent expansion of the eligibility of low-income pregnant women for Medicaid-funded prenatal care may be jeopardized by undersupplies of obstetricians and gynecologists (OB/GYNs) in rural and urban low-income areas and by widely reported declines in the number of OB/GYNs willing to accept Medicaid patients. This paper examines the availability of office-based obstetric care to Medicaid patients in Illinois. We present and test a model of the determinants of Medicaid participation by private, office-based OB/GYNs that highlights the role of residential segregation and practice economics. We find that a large growth in demand for obstetrical care or the enhancement of Medicaid fees is unlikely to have a major effect on OB/GYN participation in Medicaid. We conclude that improving access will require expanding the supply of providers in underserved areas.