High out-of-pocket health care costs for low- and middle-income Americans with kids have fallen due to "Obamacare," but more needs to be done to reduce their medical-related financial struggles, a new study claims.

The researchers examined data from 2000 to 2017 on more than 92,000 U.S. families with one or more children under 18 and one or more adult parents or guardians.

Families with out-of-pocket health care costs above a set percentage of their annual income (for example, 3.5% of incomes below $20,000, or 8.4% of those at $75,000) were said to have high financial burdens. Those whose out-of-pocket costs exceeded 10% of their annual income were classified as having extreme financial burdens.