State Medicaid Expansion Policies were Associated with Reduced Rates of Congenital Syphilis, 2008-2022

ObjectiveTo assess the relationship between adoption of Medicaid expansion policies and rates of congenital syphilis (CS) in the United States. Study Setting and DesignCases of CS have increased nearly 10-fold in the past decade. State (and D.C.) adoptions of Medicaid expansion, State Plan Amendment (SPA) optional family planning eligibility groups, and Medicaid section 1115 waiver demonstration projects have increased eligibility for family planning services. The primary outcome was the state level annual reported rate of CS per 100,000 live births. We assessed two binary policy "treatments" of interest: 1) whether a state had adopted Medicaid expansion and 2) whether a state had adopted either Medicaid expansion, a family planning waiver, or a family planning SPA. We estimated dynamic and overall treatment effects using a novel difference-in-differences estimator that accounted for variation in treatment timing. Sensitivity analyses controlled for state-level characteristics including education, poverty, unemployment, race, ethnicity, migration, and population size change. Data Sources and Analytic SampleData were collected from CDC surveillance reports and 1-year American Community Survey files from 2008-2022. Principal FindingsPre-treatment trends in CS outcomes were similar between states that implemented the Medicaid policies and those that did not. Medicaid expansion alone was associated with a significant reduction of 6.37 (95% CI: 1.94, 10.79) cases per 100,000 live births over the first three years of the policy. Adopting either Medicaid expansion, a family planning SPA, or a family planning waiver was related to a non-significant reduction of 5.06 (95% CI: -3.21, 13.33) cases per 100,000 live births. Significant reductions in CS were also found within the first year of policy adoption. ConclusionsThis analysis found Medicaid expansion policies were associated with reductions in CS rates. Increasing access to family planning services through Medicaid programs might reduce CS even shortly after policy adoption.