A researcher looking into the deaths as a result of neglect at the Bethany mother and baby home in Dublin has discovered a further 200 graves, which date between 1922 and 1949.
Many of the babies in the Bethany Home died from malnutrition and their deaths were never recorded.
Niall Meehan, a Griffith College lecturer, has previously discovered 40 unmarked graves, but he has now uncovered a further 200.
Meehan has published his discoveries in the publication "History Ireland."
He said 54 of the children's bodies which were found died from convulsions, 41 from heart failure and 26 from malnutrition. Nineteen of the babies were still born.
Two thirds of these deaths of the babies in unmarked graves happened between 1935 and 1944 and therefore they should have been declared. Run by evangelical members of the Church of Ireland,the home had no formal connection to the Church.
As well as being a home for mothers and children, it was a place of detention for women convicted of theft, prostitution, infanticide and birth concealment.
In 1934, a new law was brought in Ireland, the Maternity Act, whereby child deaths would have to be registered.
In his article in "History Ireland" he says, "The Irish State failed to do anything substantive about death, neglect and export of children in a home it inspected, to which its courts sent convicted women and young people.
"It misused its Maternity Act inspection regime to achieve merely a level sectarian playing field. The state then delayed providing financial resources throughout the 1940s, until recognition under the 1939 Public Assistance Act was achieved in 1948. Had it been otherwise lives might have been spared and life experiences improved."
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