The fumes won't hurt you either. I dye my hair, but I don't use ammonia dyes (they're worse for your hair anyway). If you do use ammonia based dyes the ammonia can make you feel sick because it's such a strong smell. I work in chicken houses, and there is a strong ammonia smell sometimes and my doctor said it's fine as long as the smell doesn't make me sick.
Do it in a well ventied room then you can wait outside till it's time to wash out that's what I do.
Perfectly fine, just make sure it's in a well-ventilated area. The only thing is due to hormones from pregnancy, the result may be different than you're used to. The color may take differently because of the change in your hair's chemistry from all those hormones.
It's perfectly ok to dye your hair as long as you are not ingesting the fumes.
Im about to do.mine. I heard it best to at least wait til the second trimester.