About 22,000 people held a rally outside Ireland's parliament building on Saturday urging the government to conserve strict abortion laws and protect "the right of the unborn child".
Pro-life activists, backed by the Catholic Church, called on Ireland's socially conservative prime minister not to introduce planned legislation that would loosen some of the world's most restrictive regulations on abortion.
The death in November of a 31-year old Indian woman who was denied an abortion of her dying fetus and later died of blood poisoning has intensified the hugely divisive debate in the predominantly Catholic country.
Ireland, the only EU member state that currently outlaws the procedure, has committed to legislate and introduce regulations to allow abortion if there is a real and substantial risk to a woman's life, after the European Court of Human Rights criticized the current regime.
Pro-life activists say Prime Minister Enda Kenny's ruling Fine Gael party is reneging on an election pledge not to introduce new laws allowing the procedure.
"The facts are simple ... Irish medical practice allows doctors to intervene to ensure women receive whatever treatments are necessary to safeguard their lives, even where this unavoidably results in the death of the baby," said Caroline Simons, spokeswoman for the pro-life campaign.
Ireland's Supreme Court ruled in 1992 that abortion was permitted when a woman's life was at risk but successive governments have avoided legislating for it over fears it could alienate conservative voters.
Five senior Catholic bishops attended the rally that took place after the Archbishop of Dublin held prayers for "the child in the womb" at a nearby church.
The Catholic Church, which dominated politics in Ireland until the 1980s, has lost much of its influence over social affairs and relations are at an all-time low with the government in the wake of years of clerical sex abuse scandals.
The death of Savita Halappanavar, who repeatedly asked for an abortion while she was miscarrying, highlighted the lack of clarity in Irish law that leaves doctors in a legally risky position. Her death is currently under inquest.
After her death, pro-choice activists held protests across Ireland urging the government to legislate to explicitly allow abortion when the health of a mother is at risk.
Smaller numbers of pro-choice activists took to Dublin's streets on Saturday to hold a silent counter-demonstration.
"It is inspiring to see so many pro-choice groups and individuals working together to fight for the rights that we deserve ... we are the majority," the group said in a statement.
(Reporting by Stephen Mangan; Editing by Jason Webb)