Thousands died at mother and baby homes over many decades.
A number of the unmarried mothers never spoke about this to other family members, the commission added.
It said: “Despite the fact that thousands of babies died, the commission is aware of only a few mothers, who were not in the institution when the child died, who subsequently sought information on the burial locations of their children.
“At least one was given incorrect information – this was unforgivable.”
One of the most notorious homes was at Tuam in Co Galway in the west of Ireland, where significant human remains were found.