A nonpartisan report to Congress is raising new questions about a key provision of federal health care law: a compromise on abortion that allowed the legislation to pass in 2010.

The Government Accountability Office said in a report released late Monday that only 1 of 18 insurers it reviewed was separately itemizing a charge for coverage of on enrollees' bills.

The 2010 compromise that President Barack Obama sealed with conservative Democrats stipulated that no federal funds would be used to pay for elective abortions.

The GAO review did not address the fundamental issue of whether federal subsidies are being used for elective abortions, but abortion opponents said the findings underscore their view that the compromise is an accounting gimmick.

The administration says the policy may require additional clarification.