Legal now, through the first three months of pregnancy:

But the debate in Mexico appeared far from over. Opponents vowed to challenge the law before the Supreme Court, saying it violates the Mexican constitution’s protection of individual rights.

"This is a step backward for democracy," said Armando Martinez, the leader of a Catholic lawyers’ group that has petitioned the leftist-dominated legislature for a referendum on the issue.

The church has played a vocal role in protesting the measure, which was also opposed by President Felipe Calderon’s conservative National Action Party. Mexico City Cardinal Norberto Rivera led a march through the capital last month in opposition to the bill, pushing the limits of Mexico’s constitutional ban on political activity by religious groups.

The Archdiocese said Tuesday that it would "evaluate the moral consequences of the reforms" and Rivera would have no public comment until Sunday.

The bill, approved 46-19, with one abstention, will take effect with the expected signing by the city’s leftist mayor. The new law will require city hospitals to provide the procedure in the first trimester and opens the way for private abortion clinics. Girls under 18 would have to get their parents’ consent.

The procedure will be almost free for poor or uninsured city residents. Mexico City is a federal district similar to Washington, D.C., with its own legislature. The district includes the capital and its suburbs and is home to about 20 million people.

Photo: Abortion activists celebrate.