I dyed my hair every 6 weeks for like 10 years. through my pregnancy and breastfeeding too. it's good to be in a well ventilated area, but none of that stuff permeates your skin, so it's perfectly fine
If your using ammonia type or bleach I would just make sure your getting as much ventilation as possible.. But there are kinds that don't use either like splat if your doing a bright color.