Controversial. This is controversial. Conventional thinking is that any exposure to chemicals is not a good idea during pregnancy. The companies would like you to continue using their "safe" products of course. My suggestion is to avoid anything chemical during a pregnancy. Personal vanity sometimes should take a back seat to making the beautiful child inside.
Maybe. On the other hand, there are no studies liking hair dye to any problems. Be sure to use in a well ventilated area.