Paint and polish are fine. If you are getting acrylics, hold off until your 2nd trimester. The fumes are really not good for you. The chemicals you can inhale in a nail salon are linked to so many serious health problems.
Be careful about cuticle cutting, whirlpools for your feet, or other instruments that can potentially spread bacteria. Most pregnant women are more susceptible to infection. Check the salon's credentials-- they should be posted. The health dept inspects them.
Also, you could suddenly have an allergy to any of the products that you used to be fine with. Some women become allergic to lotions, acrylic nails, or polish removers. You don't want to have an allergic reaction in your 1st trimester. I'd do a quick coat of paint at home and wait it out a few weeks to be on the safe side.
My mom became allergic to acrylics after having my brother. It was AWFUL!
at 7:26 PM on Feb. 4, 2010