Though thousands of new mothers gained insurance coverage following implementation of the coverage provisions of the Affordable Care Act (ACA) in 2014, there has been little documentation of changes in their health care access and affordability. This brief examines changes in access to and affordability of health care services for new mothers under the ACA using data from the National Health Interview Survey. Comparing data from 2011–13 and 2015–18, we find that new mothers were less likely to report having unmet health care needs due to cost and being very worried about paying their medical bills. In 2015–18, new mothers were more likely to report having seen a general doctor and received a flu vaccine in the past 12 months than in 2011–13. Even after these improvements, more than 1 in 10 new mothers remained uninsured, and nearly 50 percent were at least somewhat worried about paying their medical bills. Proposals to extend postpartum Medicaid coverage for up to one year could benefit some of these mothers, but additional progress would likely require broader coverage expansions through Medicaid or the Marketplace.