The MultiTerm .mdf file has ballooned to 650Mb in size for my Termbase (using MultiTerm and Studio 2019). What should I do?

I noticed that one of the .mdf files for my TermBase has exploded in size from around 500 kb to 650 Mb (!) in the course of a few days. Any bright suggestions other than exporting the contents of that Termbase into new one and then deleting the files from the old one?

650Mb file