I'm a hairstylist and you can definitely color your hair. Most doctors say to wait until the second trimester. L'Oréal professional has a line called Inoa which is an oil based color as opposed to ammonia. I have colored many pregnant women's hair and worked with a lot of women that worked in the salon their whole pregnancy with no problems at all. That being said, if you're really worried about it don't do it.
I wouldn't risk it. My Dr said not to. And honestly if there is even the smallest risk, I wouldn't take it.
My doctor said during first trimester but I didn't at all during my pregnancy because I didn't feel comfortable doing it.
Ask most doctors and hair stylists. They will say yes, as long as you're in a well ventilated area.
No. They ask you to stay away from dyeing your hair because of the commercials.