With votes counted from 30 of Ireland's 40 constituencies, results from the nationwide referendum showed that 67.3 per cent of citizens opted to remove the Eighth Amendment from the constitution, while 32.7 per cent voted to retain it. Turnout was 64.5 per cent.

Voters inserted the original amendment in the constitution in 1983 by a margin of 2-1, and it "acknowledges the right to life of the unborn and, with due regard to the equal right to life of the mother, guarantees in its laws to respect, and, as far as practicable, by its laws to defend and vindicate that right."

That text will now be deleted and replaced with an article stating that "provision may be made by law for the regulation of termination of pregnancy."

Minister for Health Simon Harris has said he would introduce legislation that would allow abortion on demand up to 12 weeks, up to 24 weeks on unspecified grounds for the health of the mother, and up to birth where the child is diagnosed with a life-limiting condition that means he or she may not live long after birth.

An exit poll conducted by the Ireland's national broadcaster RTE asked voters what motivated them to opt for either "yes" or "no." Among "yes" voters, the most important issues were the right to choose (84 per cent), the health or life of the woman (69 per cent), and pregnancy as a result of rape (52 per cent).

Among "no" voters, they cited the right to life of the unborn (76 per cent), the right to live of those with Down syndrome or other disabilities (36 per cent), and religious views (28 per cent).

John McGuirk, spokesman for Save the Eighth, which campaigned for a "no" vote, described the outcome as "a tragedy of historic proportions."

"The Eighth Amendment did not create a right to life for the unborn child – it merely acknowledged that such a right exists, has always existed and will always exist," he said, insisting that "a wrong does not become right simply because a majority support it."

"We are so proud of all of those who stood with us in this campaign – our supporters, our donors, our families and our loved ones," he said. "This campaign took a huge personal toll on all of us who were involved, and we have been so grateful for their support."

Insisting that pro-life campaigners will continue their efforts, McGuirk told Catholic News Service: "Shortly, legislation will be introduced that will allow babies to be killed in our country. We will oppose that legislation. If and when abortion clinics are opened in Ireland, because of the inability of the government to keep their promise about a (general-practitioner-led health) service, we will oppose that as well.

"Abortion was wrong yesterday. It remains wrong today. The constitution has changed, but the facts have not," he said.

Ruth Cullen of the LoveBoth campaign insisted that the organization will try to ensure that the Irish prime minister, or Taoiseach, Leo Varadkar, is true to his pledge that the government will work to ensure that abortions are rare.

No matter what happens in the coming days, weeks and months, our work will continue to protect unborn babies and their mothers #LoveBoth #WeWillOvercome

— LoveBoth (Official) (@loveboth8) May 26, 2018

"We will hold the Taoiseach to his promise that repeal would only lead to abortion in very restrictive circumstances. He gave his word on this, now he must deliver on it. No doubt many people voted for repeal based on the Taoiseach's promises in this regard," she said.

Commenting on the campaign, Cullen said: "We are immensely proud and grateful to all our volunteers throughout the country who worked tirelessly over recent months to ensure unborn babies would not be deprived of legal protections.

"The campaign to protect unborn babies will endure," she said.

Eamonn Conway, a theologian at Mary Immaculate College in Limerick, told Catholic News Service he was "greatly saddened" by the result. However, he pointed out that "the truth is that the Irish Constitution merely recognized the right to life that is antecedent to all law. This most fundamental of all human rights is not extinguished or diminished because our constitution no longer acknowledges it. What is diminished is our constitution," he said.

Conway said he believes "the task facing the Catholic Church now is to ensure that it makes every effort to accompany with the healing compassion of Christ everyone caught up in the tragic circumstances that surround an abortion ... from grieving parents to medical practitioners."

Archbishop Eamon Martin, primate of All-Ireland, was expected to address the referendum outcome during a homily at the country's national Marian shrine at Knock, County Mayo, May 27.