Sinn Féin Deputy First Minister Martin McGuinness has said political parties have a “duty and responsibility” to address the issue of fatal foetal abnormality as his party ardfheis prepares to debate an abortion motion.

Mr McGuinness said he had been moved by meeting Sarah Ewart, a young woman who travelled to England after the baby she was carrying was diagnosed with anencephaly, a severe brain abnormality.

“I was one of those within Sinn Féin who met with Sarah Ewart, a young woman who went through a very traumatic experience some time ago whenever doctors decided that her baby had anencephaly,” he said.

“It was one of the most heartbreaking meetings I was ever at alongside herself and her mother,” Mr McGuinness said.

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“That represents a real challenge to all of us to be compassionate and to recognise that people go through traumatic experiences in their lives political parties have a duty and a responsibility to deal with those situations.”

Mr McGuinness was speaking to reporters as the ardfheis got underway. Sinn Féin leader Gerry Adams said the party debate on the issue was “very necessary”.

Earlier this week, The Irish Times reported Sinn Féin TD Peadar Tóibín will not support the ardfheis motion on allowing abortion in fatal foetal abnormality cases which is strongly backed by the party leadership.

Mr Tóibín, who was disciplined for failing to vote with his party in favour of proposed X case legislation in 2012, told The Irish Times he was opposed to the proposal coming before the ardfheis this week.

“I would object to seeing it pass because I think children with a diagnosis of fatal foetal abnormality should have an equal right to life as everyone else,” he said.

Deputy leader Mary­Lou McDonald, launching the ardfheis programme earlier this week, said she was “very strongly recommending” her party’s ardfheis backs the motion to address what she described as a “policy gap”.

The motion from the James Connolly cumann in Ballyfermot, Dublin, calls for legal frameworks to be introduced in the Republic and Northern Ireland to allow women access abortion services “under these limited circumstances”, referring to fatal foetal abnormality.