I had this problem when i was pregnant, and eventually had to have them cut off at the jewellers (i tried the things mentioned above but with no luck) If it's something that's temporary, then she might be better off just waiting, if not and the above don't work, get to the jewellers. If she knows which part of the ring the hallmark is on, that would be better, so they don't cut through it.
As a very annoying aside (and i apologise profusely in advance, but i just can't help myself) you don't need ANY apostrophes in your post. Please please don't be cross with me, i literally can't help myself :)