Only ammonia free hair dye, and do it in a week ventilated room, the fumes is what you want to avoid
I'm 34 weeks and I've gotten my hair professionally dyed twice.once in the beginning and once a week ago.. Haven't had any trouble.
You can use any die just be carefull as might not take as well as you wish
My moms a cosmetologist and says its compleatly fine to die your hair wile pregnant as long as your in a well ventilated aria... Ive died my hair at begining of my pregnancy and will be doing it again in a few weeks
I bleach my hair, I promise, you'll be fine