It is safe. Make sure they salon is well-ventilated. I haven't done research into UV gel manicures, personally. I heard ONE person say that the UV light is a carcinogen, therefore you shouldn't be doing it during pregnancy, but every pregnancy resource I've consulted says there is nothing wrong with getting manicures and pedicures during pregnancy.
It is safe to get a Mani/pedi while pregnant unless you are alergic to anything they use while doing one and if just the smell bothers you you can always wear a mask like the ones people wear when mowing can be store bought only reason I have not had a mani /pedi done or even painted my nials is cause even wearing a mask the smells from nail salon bothers me same with nail polish and nail polish remover.
I get mine done all the time as well. My doctor is always commenting on how cute my nails are and asked where I get them done. I'm sure if it was dangerous she would be telling me not to go.
I get my nails and toes done all the time. If the smell is too strong for you then I would recommend getting a mask to wear while you are there. I do not believe the chemicals can do any harm to you unless you drink them.