MEXICO CITY, Mexico (CNN) -- An effort to overturn a law passed last year decriminalizing abortion in Mexico's capital appears doomed, an observer said Wednesday.
The votes of four of the 11 Supreme Court ministers would have been needed to invalidate last year's changes that allowed first-trimester abortions in the capital of this overwhelmingly Roman Catholic country.
But -- in comments Tuesday and Wednesday -- eight of the ministers argued against the proposed change, said Maria Luisa Sanchez Fuentes, executive director of the Information Group on Reproductive Choice (GIRE).
A formal vote was slated to be held Thursday.
The proposal was put forth by Supreme Court Minister Aguirre Sandino, who argues that the law is unconstitutional because life should be protected from the moment of conception.
"The ministers that voted against his proposal say there is no place explicitly in the Mexican constitution or in international law that says life should be protected from the moment of conception," said Sanchez, one of about 150 people inside the courtroom.
"There is always a flexibility and exceptions," she said, citing the right to kill in self-defense or to carry out a hunger strike as examples.
Outside the capital, abortion is legal only in cases of rape, if the mother's life is in danger or if the fetus is badly deformed.
Those who defend the current law say that it has helped save the lives of hundreds of young women who otherwise would have sought abortions at clandestine, unsafe clinics.
Their opponents say the measure had the opposite effect. "What they did with this, they legalized clandestine abortion, they gave legality to these pseudodoctors to open their clinics and continue operating as they are doing, and now, they're no longer doing it in secret, they're doing it openly," said Serrano Limon, an anti-abortion rights advocate, in an interview last week.