BALTIMORE — With states under pressure to cut their budgets and federal stimulus money gone, low-income working parents are facing a paradox. Just when they have to work longer hours to make ends meet, they are losing access to the thing they need most to stay on the job: a government subsidy that helps pay for child care.

The subsidy, a mix of federal and state funds that reimburses child care providers on behalf of families, is critical to the lives of poor women. But it has been eaten away over the years by inflation and growing need and recently by state budget cuts, leaving parents struggling to find other arrangements to stay employed.

“States have dropped their investment in child care substantially,” said Linda Saterfield, vice chairwoman of the National Association of State Child Care Administrators, who oversees child care for the state of Illinois. “We’re being expected to do more with less.” Her state has toughened eligibility for the subsidies and raised co-payments from families to cover the growing demand.

Sheontay Smith, a single mother in Baltimore, and her son are among nearly 8,000 families on a waiting list for the subsidy in Maryland. Pennsylvania’s list doubled since last year to more than 10,000 children, and Arkansas’s quadrupled to 11,000, according to the National Women’s Law Center.