Public health insurance and medical treatment: the equalizing impact of the Medicaid expansions

We investigate the impact of expanding public health insurance on the medical treatment received by women at childbirth, using Vital Statistics data on every birth in the US over the 1987-1992 period. The effects of insurance status on treatment are identified using the tremendous variation in eligibility for public insurance coverage under the Medicaid program over this period. Among low education mothers who were largely uninsured before being made eligible for Medicaid, eligibility for this program was associated with significant increases in the use of a variety of obstetric procedures. Among women with more education, however, there is a countervailing effect on procedure use. Most of these women had private insurance before becoming Medicaid-eligible, and some may have been 'crowded out' onto the public program, moving from insurance which reimburses medical care more generously to insurance with much less generous reimbursement. This movement was accompanied by reductions in procedure use. Thus, on net, the Medicaid expansions had an equalizing effect, increasing the treatment intensity of the previously uninsured while lowering it among the previously insured. (C) 2001 Elsevier Science B.V. All rights reserved.