Hair Dye Safe?

Betthany • 22. Married my husband 6/28/14. Expecting our first little boy 1/8/15. Stay at home wife currently.
Im now in my second trimester and was wondering if it is safe to dye my hair. I forgot to ask at my last OB appointment. For only being 22, I have more grays than I should lol. Obviously, if it isn't safe, I'm fine with waiting to dye it until after delivery. Also, anyone know if it's safe while breast feeding? Any info would be extremely helpful.