Mitigating Postpartum Coverage Loss during the Phe Unwinding: Evidence from Illinois’ 12-Month Medicaid Extension

Background and Purpose: Historically, Medicaid provided higher income eligibility thresholds for pregnant individuals but limited postpartum coverage to 60 days following delivery. This abrupt cutoff created coverage disruptions during a period when many pregnancy-related complications and health crises emerge. In 2021, Illinois became the first state to extend postpartum coverage to 12 months, a policy later adopted by many states. The end of the Public Health Emergency (PHE) continuous enrollment provision in 2023 created a natural experiment to evaluate this policy. As non-expansion states reverted to the 60-day cutoff during the unwinding phase, low-income mothers faced increased risks of coverage loss. This study examines the effects of the postpartum extension on coverage continuity and administrative churning using multi-state Medicaid administrative data.

Methods: We used Medicaid enrollment and claims data from Illinois, Iowa, and Wisconsin from 2018 to 2024. The sample included individuals with Medicaid-covered deliveries, eligible under higher pregnancy-related income thresholds (e.g., up to ~200% of the federal poverty level in Illinois). Using a quasi-experimental design with comparison states, we applied difference-in-differences and event study approaches to compare postpartum coverage outcomes in Illinois (treatment) versus Iowa and Wisconsin (controls) across three periods: pre-extension (2018–February 2020), PHE (March 2020–May 2023), and post-extension unwinding (June 2023–2024). The DiD framework estimates changes in Illinois relative to changes in the comparison states. Models were estimated using linear probability models with state and time fixed effects and adjusted for sociodemographic characteristics. Outcomes included continuous enrollment at 6, 9, and 12 months postpartum and churning, defined as re-enrollment within 12 months after post-60-day coverage loss.

Results: Event study estimates confirmed the parallel trends assumption prior to the unwinding. During the unwinding phase, DiD models yielded a statistically significant, positive coefficient for the interaction term, indicating that the Illinois 12-month extension substantially increased the probability of maintaining continuous enrollment at 6, 9, and 12 months postpartum relative to the control states. Furthermore, DiD estimates demonstrated a significant reduction in the likelihood of procedural disenrollment and subsequent re-enrollment. The policy effectively prevented the abrupt termination of coverage at 60 days postpartum, with Illinois beneficiaries exhibiting a significantly higher probability of coverage continuity compared to their counterparts in non-extension states.

Conclusions and Implications: Findings indicate that extending postpartum Medicaid eligibility to 12 months helps address a structural mismatch between coverage policy and the timing of maternal health risks. By eliminating the 60-day cutoff, the policy reduced coverage loss and administrative churn during a highly vulnerable period. These effects were evident during the PHE unwinding, demonstrating how eligibility design can shape coverage stability during large-scale redetermination processes and increased disenrollment risks. The extension also reduced exposure to complex renewal procedures and administrative burdens that disproportionately affect low-income mothers. As states navigate the post-PHE redetermination period, these findings support broader adoption of 12-month postpartum coverage. Aligning eligibility policies with maternal health needs is a key lever for improving coverage continuity and protecting vulnerable populations.