I was 6-7months pregnant when I had two teeth pulled out. I had an absess and was on antibiotics and panadeine forte and nothing touched me. I couldn't have it removed until the absess was clearing but after a week they took it out. I wouldn't advise it if you didn't need to go (like for a check up etc) but if you have a tooth ache I would definately go. The drugs they use for any procedure is localised to that area (the mouth) and shouldn't be systemic (everywhere) well thats what I was told.
If there is a tooth problem I also wouldn't want to wait to have it treated as it might mean loosing that tooth later on or it been harder to fix.