(HealthDay News) — Unexpectedly high numbers of Americans who were previously eligible for Medicaid but were not enrolled are now signing up, and states are facing unanticipated costs for that coverage.

Part of the reason why millions of these people have now decided to sign up for Medicaid is the widespread publicity about the need to be insured under the federal health care law, according to the Associated Press

Under the law, states can expand Medicaid eligibility to people with incomes up to 138% of the federal poverty line — about $16,100 for an individual. The federal government will pay the entire cost of coverage through 2016. After that, Washington’s share will gradually be reduced to 90%.

Continue Reading

RELATED: General Medical News

This method of expanding Medicaid coverage has been accepted by about half the states. In states that don’t take this approach, the federal government will pay an average of about 60% of the cost of coverage for people who were previously Medicaid-eligible, the AP reported. 

However, even states that opposed the health care law have seen significant rises in Medicaid enrollment, the AP reported. For example, there have been increases of 10% in Montana, 6% in Georgia, and 5% in South Carolina, according to the market research firm Avalere Health.

“Anyone who didn’t budget for this is going to be behind the eight ball,” Avalere CEO Dan Mendelson told the AP. “It’s the kind of thing governors will want to discuss with the White House.”