The country's leaders supported a "yes", an outcome that would repeal a 1983 constitutional amendment requiring authorities to treat a fetus and its mother as equals under the law.
Throughout the campaign, supporters of the "Yes" side argued that the ban does not prevent abortions but forces women to travel to the United Kingdom - at an average rate of nine a day - to terminate unwanted pregnancies They also pointed out that no one under the age of 50 had had the opportunity to vote on abortion law, despite it remaining a high profile issue in public debate for decades, particularly since the 2012 case of Savita Halappanavar, who died from sepsis after doctors in a Galway hospital refused to terminate her pregnancy when she was miscarrying.
Ireland does not give its expatriates absentee ballots or the option to vote at embassies.
However, campaign group Save The 8th says politicians are "effectively seeking a licence to kill pre-born babies, and to introduce an abortion model that is in many ways even more extreme than the British regime".
These proposed changes, the archbishop concluded, have united all Christian traditions [around the "No" campaign].
Ireland, like the United States, has very different patterns of voting in urban areas and in the countryside.
Lava from Hawaii volcano enters ocean from 3 flows
There continues to be intermittent explosions at the summit that have been sending plumes of ash into the sky. Geological Survey has posted footage of the odd blue burning flames on its Facebook and Twitter accounts.
"Yes" campaigners have argued that with over 3,000 women traveling to Britain each year for terminations - a right enshrined in a 1992 referendum - and others ordering pills illegally online, abortion is already a reality in Ireland.
They correctly perceived that Ireland was gradually becoming a more secular country, and wanted to create a bulwark against the introduction of abortion that would be hard to reverse.
No social issue has divided Ireland's 4.8 million people as sharply as abortion, which was pushed up the political agenda by the death in 2012 of a 31-year-old Indian immigrant from a septic miscarriage after she was refused a termination.
Reacting to the exit polls, Taoiseach Leo Varadkar, a vocal proponent of liberalisation, tweeted on Friday night: "Thank you to everyone who voted today". That meant, in practice, that abortion was strictly against the law.
Later abortions would be allowed in special cases. "Whether you agree or disagree, it shouldn't be the government or anyone else making that decision".
"It's an added bonus that I get to see my family, but the referendum is the only reason I came back to be honest", she said.
Ireland's prime minister, Leo Varadkar, has said almost 200,000 women have traveled to Britain to terminate pregnancies in the 35 years since the amendment was passed. Numerous anti-abortion signs showed photographs of foetuses.
Between 12 and 24 weeks, abortion will be available only in cases of fatal foetal abnormality, a risk to a woman's life or a risk of serious harm to the health of the mother.