Coffee is supposed to help prevent stones from forming, but I have no idea whether it can helps any with existing ones.


Not true...the opposite...coffiee causes kidny stones.
I have gone through this three times in my life.
It is one of the moste painfull things you can experience.
Grab your top lip and pull it back over your head....something like that.
The last one eas about 5 years ago.
I heard beer and cranberry juice...not together:))....
I started drinking beer after that...max 3 or 4 a day.
No problems since.
Be carefull OP stones can kill you if it gets stuck!
GOOD LUCK with the birth.