They can't smell what we smell but chemicals we enhale affect them. Just like we shouldn't be around 2nd hand smoke because it affects them
I've done it over three times. I don't think it will affect our baby's is not like they can smell what we smell. Unless we were eating the dye than it's something else. Well that's my opinion.. :)
I think 13 weeks is when it's safe :)
Do it in a well ventilated area too. Just to be safe :)
Cover your nose and mouth while doing so, and ammonia free.
I did. Get the ammonia free brands. My Dr says there's no risk to the baby to dye your hair.