The U.S. adaptation of the text to the missal was supported by 179 bishops, with one voting against and one abstaining.I'm sure there was an excellent reason to either abstain or vote against this. Just because I can't think of one doesn't mean anything.
The Mass in Thanksgiving for Life was originally proposed in 1990 by Cardinal John O'Connor of New York, who founded the Sisters of Life and died in 2000.