I doubt there is any formal law or rule about this in the Roman Church, or was in the past. It's more of a hang up I think, perhaps that sort of Baltimore Catechism nonsense that sometimes led to silly hang ups and scruples. I think there are some good points to the laity not chewing the host but I don't think it's as big a deal as traditionalists think.
The worse thing is communion in the hand and having lay men and women give the Precious Blood. Sometimes there is only one priest and no deacon but I think the liberals still use Eucharistic laymen, and moreso women, to go against the superior place of holy orders and the superior place of men in the Church regarding leadership. Women certainly play an important part but they never had holy orders, even in the days of deaconesses. And allowing a women to handle the Eucharistic gifts I do not like when there are plenty of men to do so, even deacons. In the old days one priest gave out the body and everybody knelt altar rail (Western) as the priest went to each person. And he could use a deacon or layMAN if he needed help with the blood in the modern practice. Placing men and women on an equal level in Church practices is problematic and I do not think I am just raising these points to get a rise out of the St. Paul "women be silent" thing. There has always been an idea that women may play an important place, but there is a certain, forgive me for sounding "old fashioned", rule of submissiveness that they are bound to by virtue of the the sin of Eve. I know in the early days of Church women may have sometimes, but that was stopped in both the East and West. I am not totally against the idea of deaconesses, but there will never be women priests and they will always be bound to the command of the Apostle, "women be silent in Church", though the Church interprets that accordingly and we should not be rigorists.