If a mother performs Hajj while pregnant, are pebbles thrown on behalf of the fetus during the stoning ritual (rami al-jamarat)?

It is not legislated to stone the Jamarat on behalf of a fetus, as we are not aware of any such saying, and because the validity of the stoning requires entering into the state of Ihram for Hajj and standing at Arafat, neither of which can be fulfilled by a fetus.