Once I rule your planet I shall have all humans lasered to remove all of their hair follicles, including the ones on your head. Then you will not need to ask such questions.

Yet since you asked: if you can not smell your hair dye, it is safe. If you can smell your hair dye (or nail polish or remover for that matter) it is not safe. The fumes are harmful to your developing child. You must also never lighten your hair while pregnant if you are going all the way to your scalp; you to not want the bleaching agent to touch your skin whatsoever.

Also be aware that dye will affect your hair differently while pregnant because of your hormones.

I always do. I've been wanting to get a nice deep red with bleach blonde highlights but I also change my mind as soon as I've had it colored during pregnancy so I've been holding off this time lol sometimes the color doesn't take the way it usually would

Yea I have his whole pregnancy so far and as long as it’s well ventilated you should be fine. Just be ready for your hair to possibly not hold the dye as well or the color to be slightly off.

It'll be no problem as long as you're in a well ventilated area

It's safe. I do brown underneath my blonde all the time.