Many women in Argentina use misoprostol to end first-trimester pregnancies.
President Mauricio Macri, who is against abortion, had already said he would sign the bill after the country's lower house chose to support it - but senators voted it down 38 to 31. Abortion is now legal only if the pregnancy is the result of sexual assault or if the mother's life is in danger.
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Activists in favour of the legalization of abortion comfort each other outside the National Congress in Buenos Aires after senators rejected the bill to legalize abortion.
Backers of the measure said legalizing abortion would save the life of many women who now turn to risky illegal abortions. A vote could come Wednesday or early Thursday.
Chile's constitutional Court a year ago upheld legislation ending the Andean nation's absolute ban on abortions, permitting the procedure when a woman's life is in danger, when a fetus is not viable or in cases of rape.
US -based organizations such as Live Action, Human Defense Initiative and the National Right to Life Committee expressed their opposition to the bill as well.
The Pope also reiterated the Catholic Church's opposition to abortion this year, urging families "to accept the children that God gives them". We will continue to stand with women in Argentina.
For many of them, the methods used to induce an abortion include using an IV tube with a sharp wire clothes hanger or a knitting needle to try to break the amniotic sac inside womb.
Hundreds of doctors have staged anti-abortion protests, in one case laying their white medical coats on the ground outside the presidential palace.
Abortion rights supporters wore green scarves while anti-abortion activists donned baby blue.
The move was also condemned by Amnesty International, which said Argentina had squandered an historic opportunity.
The proposal can not be brought up for debate until next year, but Argentina's Senate is set to discuss abortion again late this month when it considers reforms to the country's penal code, reported La Nación. There are three exceptions: if a woman is raped, pregnancy puts her life in danger, or the fetus is brain-dead. Had the proposal been adopted, Argentina would have become the largest Latin American nation to legalize abortion, after Cuba.