A yearly gathering of abortion-rights opponents in Washington is set to spark a pitched battle over the healthcare bill before Congress this week.

The annual March for Life, scheduled for Friday, Jan. 22, will take aim at the health reform efforts, which opponents argue subsidizes coverage of abortions.

At least tens of thousands of opponents of abortion rights will descend on D.C. as Democratic lawmakers move toward finishing their work on historic health reform legislation.

But a key hangup, which is yet to be resolved among lawmakers, has been abortion, with amendments to the the House and Senate bills leaving members' votes on final passage up in the air.

An amendment by Rep. Bart Stupak (D-Mich.) was included in the House legislation, though abortion-rights supporters have said they expect that provision to be stripped in the final bill. A less stringent amendment was included in the Senate's legislation to win the crucial support of Sen. Ben Nelson (D-Neb.), though abortion-rights opponents have said that measure falls short of ensuring federal dollars won't fund abortion services.

The March for Life will set the stage Friday for a public demonstration against the current bill, as Democratic leaders work to cobble together the votes to finally clear their bill from the House and Senate.

Abortion-rights opponents have said they would vote against a final deal if it included language similar to that offered by Stupak, though the Michigan congressman, along with groups opposing abortion rights, have threatened to oppose the bill if it falls short of the language approved by the House in November.

Playing into the heightened campaign over healthcare have been the actions of former Rep. Marilyn Musgrave (R-Colo.), who's led a tour of nine cities in the Midwest to pressure Democrats who oppose abortion rights to oppose the underlying bill if it isn't aggressive enough in cutting off funds for abortion services.

Musgrave's campaign has included a $45,000 radio ad campaign on behalf of the Susan B. Anthony list group, and potential plans to expand her campaign to target centrist Democrats in the south.

That campaign, combined with this week's public demonstrations in Washington, hopes to flip on-the-fence Democrats to oppose the bill.

Healthcare reform, said one publicist for the March for life, will be "one of the biggest focal points for the March."