L.C.
Hi L.,
I'd get it taken care of now and make sure that you don't allow them to put amalgam (the silver metals bound by very toxic mercury) in your mouth. I wouldn't wait until I was pregnant and I would avoid any dental work I could while pregnant and nursing... other than cleanings. Check out this website and see what you think: http://www.iaomt.org
Good luck with pregnancy!
L.