Exit polling data suggested many voters in Ireland had made up their minds on abortion before the official campaign began eight weeks ago, academics have said.
Only a minority were swayed by the divisive and emotive public debate around the issue over recent days.
Pollsters said people were more affected by the stories of women who have suffered due to Ireland's tight restrictions, travelling to England for the procedure or taking abortion pills obtained on the internet without supervision.
Here are some of the other trends that have appeared from polls carried out for the Irish Times and RTE:
– Young versus old
The polling data suggests a huge gulf in views held by Ireland’s youngest and oldest generations.
Both exit surveys recorded support for the Yes camp at approaching 90% among 18 to 24-year-olds.
By contrast, the over-65 group was the only age bracket to vote No, with around 60% wanting to retain the Eighth Amendment.
Some extraordinary (extra-extraordinary) stuff in the detail of the Exit Poll:
- 77% Yes in Dublin
- 66% Yes in Munster
- 59% Yes in Connacht
- Majority in all age groups under 65— Richard Chambers (@newschambers) May 25, 2018
– Urban versus rural
As predicted, urban areas appear to have been more strongly in favour of repeal, at just over 70%.
But according to the polls, rural areas also voted Yes, with around 60 to 63% in favour.
– Region by region
In keeping with the urban/rural trend, Dublin had the highest Yes vote of around 78%.
In Leinster, just under two-thirds of voters (66%) backed liberalisation, with a similar figure in Munster.
In Connacht/Ulster, the figure was slightly lower at around 61%.
More than a year ago a public advisory body to the Irish Government voted in favour of having no restrictions on early pregnancy by a margin similar to the predicted outcome of Friday's referendum.
The Citizens' Assembly decided by 64% to 36% in favour of the momentous step.
The body is made up of 99 members chosen at random to represent the views of the Irish electorate.
It was established by the Oireachtas parliament to consider some of the most important issues facing Ireland in the future and began its meetings in 2016.
Its most controversial task was deciding whether to repeal the Eighth Amendment of the Irish Constitution - which gives an equal right to life to a pregnant woman and an unborn child, and prohibits abortion unless a woman's life is in danger.
When the Assembly returned its verdict the Government quickly promised a referendum and announced the date earlier this year, as well as its proposals for reform.
They drew on the Assembly's recommendations and draft provisions include that terminations would be freely available, subject to medical advice and a cooling-off period, up to 12 weeks, with more restricted provision from 12-24 weeks.
- Digital Desk and Press Association