I went and had mine done if it's too much for you just ask for a mask.
Are talking about just a common manicure or a full set?? Either way, definitely use a mask! I bring my own, I get a full set monthly and a fill in as need be, between month's. Getting a full set requires more steps and chemicals used are stronger then those of a gel set or a average manicure. My OB recommended I use a mask and wash my hands and face afterwards, which I do.
Also recommend that they turn your seat facing away from the person that's doing your nails as well as away from the products.
I've gotten my nails done quite a few times during this pregnancy, almost 38 weeks, and my Dr said to just find a well ventilated place. If I walk in and there's no fans and it smells horribly of chemicals then I walk right out. I've found the places that cost more are better because they're very well ventilated and don't smell of chemicals.
I do mine myself, using the gel nail varnish n uv lamp
It's fine.... I got mine done for most of my pregnancies...