From my experience I've noticed that every doctor has a different opinion on everything. If your OB said it was ok then I probably wouldn't worry about it too much. I would think that s/he should know better since they deal with that a little more than your GP. I would however bring up your concerns with your OB. I hope that helps. Good luck hun.
Did your primary care doctor say that it was high risk now and that you should abort? That sounds very extreme to me. You need to talk to both your OB and your primary immediately and press them on this. Even have them talk to each other! If you go on the mothering(dot)com website there is alot there about vaccinations, so maybe someone would know more.
Sorry I don't have info on the subject but I do think that abortion is not what you want here, and it sounds like you were TTC. All babies are beautiful!