Some states could run out of funding for their Children's Health Insurance Program (CHIP) as early as this month, despite recently approved spending by Congress that was expected to keep the program running through the end of March, federal health officials said Friday.
All states should have sufficient funding at least through Jan. 19 thanks to Congress' $2.85 billion infusion last month, according to the Centers for Medicare & Medicaid Services. The agency did not say which states are likely to be affected first.
"The funding ... should carry all the states through January 19th based upon best estimates of state expenditures to date," said CMS spokesman Johnathan Monroe. "However, due to a number of variables relating to state expenditure rates and reporting, we are unable to say with certainty whether there is enough funding for every state to continue its CHIP program through March 31, 2018."
The latest estimates for when federal funding runs out could cause states to soon freeze enrollment and alert parents that the program could soon shut down.
Connecticut is already warning parents that its CHIP program, known as HUSKY B, will end by Feb. 28. The state was going to shutter its program this month, but that deadline was extended after Congress allocated additional money.
"This is not enough funding to allow states to continue the program for long," the state Department of Social Services posted on its website. "It will only allow Connecticut to continue HUSKY B through February. "
Related: Congress provides short-term funding for children's health insurance
The CHIP program provides health coverage to nine million children from lower-income households that make too much money to qualify for Medicaid. Its federal authorization ended Oct. 1, and states were then forced to use unspent funds to carry them over while the House and Senate try to agree on a way to continue funding.
Congress extended funding on Dec. 21 as part of a temporary spending plan to fund the federal government through Jan. 19. Lawmakers touted that states would have money to last while they worked on a long-term funding solution.
But it's still not enough for everyone.
"Some states will begin exhausting all available funding earlier than others," a CMS official said Friday. "But the exact timing of when states will exhaust their funding is a moving target."
CMS said the agency is in discussions with states to help deal with the funding shortfall.
Related: Parents to Congress: My child depends on CHIP for health insurance
"States need to know whether they will need to find additional funding for children covered under the Medicaid CHIP program at a much lower federal matching rate, send letters to families, and re-program their eligibility systems," said Lisa Dubay, a senior fellow at the Urban Institute. "Of course, the implications for families with CHIP-eligible children cannot be understated: Parents are worried that their children will lose coverage. And they should be."
Although the program enjoys bipartisan support on Capitol Hill, the Republican-controlled House and Senate have for months been unable to agree on how to continue funding CHIP, which began in 1997.
The House plan includes a controversial funding provision — opposed by Democrats — that takes millions of dollars from the Affordable Care Act's Prevention and Public Health Fund and increases Medicare premiums for some higher-earning beneficiaries.
The Senate Finance Committee reached an agreement to extend the program for five years but did not unite around a plan on funding it.
Before the CHIP funding extension on Dec. 21, Alabama said it would freeze enrollment Jan. 1 and shut down the program Jan. 31. Colorado, Connecticut and Virginia sent letters to CHIP families warning that the program could soon end.
After the funding extension, Alabama put a hold on shutting down CHIP.
Bruce Lesley, president of First Focus, a child advocacy group, said Congress should have known its short-term funding plan was not enough.
"The math never worked on the patch, as it only bought a few weeks," he said. "Congress must get this finalized before Jan. 19."
CNNMoney's Tami Luhby contributed to this report.
Kaiser Health News is a nonprofit news service covering health issues. It is an editorially independent program of the Kaiser Family Foundation that is not affiliated with Kaiser Permanente.