In a lopsided ruling, Mexico's Supreme Court on Thursday upheld a year-old law in Mexico City legalizing abortions during the first 12 weeks of pregnancy.
The court rejected arguments by abortion opponents that the law violated the Mexican Constitution, whose protections they said covered embryos. A majority of justices said overturning the law would block the right of women to end pregnancies in the early weeks.
The vote was 8 to 3 to uphold the measure, approved in April 2007 by Mexico City's leftist-dominated government. Opponents needed support from at least eight of the 11 justices to overturn the law.
The ruling is likely to encourage similar legislative drives outside Mexico City, where abortion remains illegal except in certain cases, such as pregnancies resulting from rape or incest.
Abortion rights activists said the ruling set a precedent for state legislatures to pass measures legalizing abortion. The leftist Democratic Revolution Party, which governs Mexico City, has signaled plans to push for such laws.
The court decision was a defeat for the nation's Roman Catholic Church and the conservative National Action Party of President Felipe Calderon, which were vocal critics of the law. The federal attorney general's office and Mexico's human rights commission lodged the formal challenge.
The ruling, which came after six public hearings, pleased abortion rights advocates in a heavily Catholic nation.
Mexico City is among the few places in Latin America where women can legally terminate pregnancies apart from rape and incest cases.
"It's historic, with a huge impact on women's rights, not only in Mexico but throughout Latin America," said Maria Consuelo Mejia, who heads a group of Catholics who favor abortion rights. "No one has the right to impose a pregnancy on a woman."
Jorge Serrano Limon, who directs Pro Vida, an anti-abortion group, called the decision "a real tragedy."
"Eight justices voted against life. The fact is that a person has no protection before 12 weeks of life," he said. "It's going to spread across Mexico."
Serrano said anti-abortion forces would meet next week to decide their next move.
"We'll keep fighting," he said. "It's just going to be more difficult."
It was clear during the televised deliberations that the legalization law's opponents lacked the votes to throw it out. The court majority dismissed arguments that the Mexican Constitution protected embryos and said women's rights needed to be weighed.
"Human rights systems cannot require states to defend a right to life from conception," Justice Genaro Gongora Pimentel said. "It would mean imposing ideologies and subjective values that could sacrifice other rights that are fully identifiable."
Justice Sergio Aguirre Anguiano, who led the effort on the court to invalidate the measure, said the constitution guaranteed the right to life, and that such protections begin at conception.
He argued that Mexico City's legislature lacked authority to pass such a measure because health laws were under the purview of the federal government. But the court rejected that position in a preliminary 10-1 vote.
Mexico City lawmakers passed the measure after proponents argued that removing criminal penalties would make abortions more widely available to women of all social classes while reducing the risk of death or injury from procedures performed in underground clinics.
Illegal abortions have long been widely available, though many poor women seeking to terminate pregnancies have resorted to buying herbs from markets or prescription drugs obtained from pharmacists without a doctor's signature.
Since passage of the Mexico City law, hundreds of women have flocked to the capital for abortions in its public clinics. City officials say more than 12,600 women have had abortions since the law was approved.
The measure has saved lives, they say, citing a drop in the number of women who have died during the procedures.
But foes attacked the law as immoral and a violation of Mexican law and international conventions aimed at guaranteeing human rights. They also argued that Mexico City hospitals were overstretched and therefore unable to provide proper medical attention to women seeking abortions.
Many gynecologists in the public hospitals declared themselves as "conscientious objectors" to the law and refused to carry out the procedures. That has increased the workload of doctors who do perform abortions.
"We don't have the infrastructure," said Guadalupe Reyes Gonzalez, a Mexico City physician who stood along Paseo de la Reforma on a recent day as part of a group protesting the abortion law. "I'm here out of the love for children, and also for women."
For the most part, demonstrations were scattered and small as the deliberations began Monday.
The Catholic Church weighed in on the eve of the deliberations with a televised spot from the nation's council of bishops that said life begins at conception.
President Calderon remained largely on the sidelines of the debate, though his party is staunchly opposed to abortion.