Medicaid enrollment policies increased coverage among Black postpartum Medicaid beneficiaries, especially in states that did not previously expand Medicaid under the ACA. However, postpartum uninsurance was not eliminated, and racial inequities in uninsurance persisted. Overall, this study suggests that postpartum Medicaid extension plays an important role in improving access to postpartum maternal health care but it is not a sufficient policy intervention to address the US Black maternal health crisis.