Worldwide reproductive rights advocates joined Argentinian women in mourning the bill's defeat, but credited the country's pro-choice movement with building momentum toward securing abortion rights in Argentina as well as across Latin America, where only Uruguay, Cuba, Guyana, and Mexico City allow abortion in early pregnancy.
The bill had sought to legalize abortion during the first 14 weeks of pregnancy and would have seen Argentina join Uruguay and Cuba as the only countries in Latin America to fully decriminalize abortion.
Argentina now allows abortion only in cases of rape or risks to a woman's health and abortion rights activists say 3,000 women have died of illegal abortions since 1983. Lawmakers debated for more than 15 hours, from Wednesday into Thursday, then voted 31 in favor to 38 against.
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The move to legalize abortion in Argentina is a "public health and human rights imperative", said New York-based Human Rights Watch.
Backers of the measure said legalizing abortion would save the life of many women who now turn to unsafe illegal abortions.
Earlier in the day, scores of buses had brought people from around the country into Buenos Aires for the dueling rallies outside Congress. "Caring for life is the first human right and the duty of the state". Women found guilty of having illegal abortions can serve up to four years in prison, and medical professionals involved in such procedures can go to prison for up to six years.
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.
Speaking to a delegation of the Forum of Family Associations at the Vatican, Francis denounced today's abortion culture and urged his hearers to accept human life as it comes from the hand of God.
Abortion rights supporters wore green scarves while anti-abortion activists donned baby blue.
Celia Szusterman, trustee of the United Kingdom board of Pro-Mujer and director of the Latin America programme at the Institute for Statecraft, told CNN that the vote was "a step backward for women's rights and women's health".
Tensions ran high during the legislative debate - which lasted well into the morning - with some members of the lower chamber being barred from the Argentine Senate and the vice president hurling insults at a senator.
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.