Whenever a couple wants to name a baby, most of the time they want to use a name that has a positive meaning. For instance, bright and cheerful names are usually appealing. However, that also depends on how the name sounds. That said, the name Bertha is German
for bright and glorious.
However, according to Nameberry, their experts have said because of the fact that the German giant cannon that was used during WWI was called Big Bertha- that name has not been used at all often since then. That is because it is hard to imagine a sweet baby girl is named after a giant cannon essentially.