In the U.S., 15.7% of mothers are uninsured. That’s 5.9 million mothers or one out of every six , according to new study from the Urban Institute. We care about all parents but with Mother’s Day right around the corner, we are focusing on moms for now.

In How Are Moms Faring under the Affordable Care Act? Evidence through 2014, researchers used data from the National Health Interview Survey (NHIS) to analyze trends in mothers over time (1997-2014) and among different demographics.

The study finds that many mothers gained affordable health coverage in 2014 following the implementation of many major provisions of the Affordable Care Act, including Medicaid expansion and exchange subsidies. The uninsurance rate for mothers dropped 3.8 percentage points between 2013 (19.5%) and 2014 (15.7%).

Coverage gains were particularly large among low-income mothers (under 138% of FPL), who saw a 6.2 percentage point decline in uninsurance rates from 37.5% in 2013 to 31% in 2014. Still, this means that nearly one-third of low-income mothers are uninsured, compared to 14% of moderate-income mothers (138-400% of FPL) and just 2% of high-income mothers (>400% of FPL).

Medicaid expansion proved to be a particularly important policy for decreasing the rate of uninsurance among poor mothers. About 39% of low-income mothers living in expansion states were uninsured, compared to about 23% of low-income mothers in expansion states. States that expanded Medicaid also had far larger coverage gains for low-income women (8.1 percentage points) than non-expansion states (4.9 percentage points).

Thanks to the Affordable Care Act, mothers across the country are gaining affordable, quality health coverage. But three-fifths (61%) of all uninsured moms are low-income – and Medicaid expansion can help. Parents living in non-expansion states lack access to health care services and the financial security that Medicaid provides. Numerous studies show that when parents gain Medicaid coverage, children are more likely to get covered too which studies show helps them do better in school and develop into healthy adults. Let’s hope that next Mother’s Day, moms in all 50 states and DC will have the same opportunity to access Medicaid coverage that has so far been denied to those living in 19 reluctant states.