Abortion vote on a knife-edge in Chamber of Deputies as debate continues
According to a running tally documented by the Economía Femini(s)ta organisation, 123 lawmakers have publicly said they will vote in favour, with 121 confirming they will vote against. A further nine have yet to indicate which way they will vote.
The abortion debate has fiercely divided society. Though Argentina was the first Latin American country to legalise same-sex marriage in 2010, it remains strongly influenced by the Catholic Church and its native son, Pope Francis.
The session in the Chamber of Deputies began at 11.30am local time. It expected to continue for up to 20 hours before the vote is taken, with most expecting the vote due in the early hours of the morning, close to dawn.
Many lawmakers have said they would put their religious convictions aside to support the bill.
"Our function is to listen. It is not a personal decision, but it's about who we represent. Listening to different sectors of the province of Buenos Aires, I made the decision to vote in favour," said Fernando Espinoza of former president Cristina Fernández de Kirchner's Citizen's Unity Party.
Espinoza spoke minutes after the session opened, as several previously undecided lawmakers indicated how they intended to vote, but it was as yet unclear how the shifting positions would affect the overall result.
As in most countries in the region, abortion is currently illegal in Argentina, except in cases of rape or when the life or health of the woman is at risk.
The leader of the pro-abortion rights bloc, Daniel Lipovetzky, told the Chamber there were valid "public health reasons" why they should adopt the bill.
"We had three health ministers, with distinct visions because they belonged to distinct governments, and in this they agreed: the legalization of abortion improved healthcare for Argentine women," he said.
But Horacio Goicoechea, from the pro-government Radical Civil Union, countered that "beyond good intentions, [the bill] subverts a biological, biomedical, legal and historical order of the nation."
According to official Health Ministry statistics, over 17 percent of the 245 recorded deaths of pregnant women and girls in 2016 were due to abortion. NGOs say some 500,000 clandestine abortions a year are carried out every year.
Argentine lawmakers overcame strong Church opposition to legalise gay marriage eight years ago, but the issue of abortion has not been discussed in Congress.
President Mauricio Macri made it clear from the outset he was "in favour of life" but nevertheless encouraged open debate in Congress, after seven previous attempts failed to reach the assembly.
Argentines are as divided over the issue in the streets as in Congress. Pro- and anti-abortion groups began holding demonstrations outside Congress early Wednesday, with protesters saying they would remain until the vote is finished.
Last week an "interreligious prayer for life" was held in Buenos Aires, which was joined by leaders of the Catholic Church and other Christian currents, as well as Muslims and Jews.
Meanwhile, high-school students have taken over several Buenos Aires schools to support the decriminalisation of abortion.
"The main demands are that the bill for safe, free and legal abortion be approved, that a comprehensive sex education law is complied with, and that there be protocols against gender violence in schools," said student leader Juana Garay.
Human Rights Watch says the vote is a landmark opportunity to end a harmful policy.
"With the vote in Congress, Argentina can join the global trend toward expanding legal grounds to allow abortion and affirming the rights and dignity of women and girls," said José Miguel Vivanco, the New York-based rights group's Americas director.
On the other side, Vice-President Gabriela Michetti, from Macri's Cambiemos (Let's Change) coalition said: "We have women who die from miscarriages, there is a public health issue, but I do not accept that to improve this situation we have to limit another life."
In Latin America, unrestricted abortion is legal in Uruguay, Cuba and Mexico City. In almost all countries, it is available in case of a risk to a woman's life or in cases of rape. However, a blanket prohibition exists in the Central American states of El Salvador, Honduras and Nicaragua.