The Maryland House on Wednesday gave a gay marriage bill its preliminary okay, the AP reported.

Gay marriage backers fought off four proposed amendments to advance the bill to a third and final vote.

Before Wednesday's session, House Speaker Michael Bush warned that any changes to the bill, approved two weeks ago by the Senate, could kill it.

Keeping the bill free from amendments allows the House to send the legislation directly to Governor Martin O'Malley, who has promised to sign it into law. Any changes would send the bill back to the Senate for a second round as the clock runs out on Maryland's brief 90-day legislative session.

Delegate Andrew Serafini, a Republican from Washington County, proposed changing the name of the bill from the Civil Marriage Protection Act to the Same-Sex Marriage Act, while Democratic Delegate Aisha Braveboy of Prince George County attempted to attach an amendment that would put the measure on the ballot.

“This is an important step forward but it's not a done deal,” Morgan Meneses-Sheets, executive director of the gay rights group Equality Maryland, told gay weekly Metro Weekly. “We have to keep up the work in order to make sure this important legislation passes for all loving and committed gay and lesbian couples in Maryland.”

Opponents of gay marriage are widely expected to mount a referendum on the law, if approved by lawmakers.