Hair dye that's good for pregnancy??

Kari • Hi! Kari's the name. Preggo with my second bundle of joy! Love muffin #1 was born March ‘17. 👶🏻
So I'm five weeks and my OBGYN has said a big NO to getting my hair dyed while I'm in my first trimester but did say that natural hair dye would work.   My hairdresser could easily come to my house for a well ventilated area, but my OBGYN said its not just about venilation it's about the hair dye entering the bloodstream.  Anyone know of any commercial hair salons that use natural hair dye?  I'm dying to get my hair done!  Dying!  The grays are coming it to play.  Please help!!  I'd like to not have to wait until my second trimester.  I have two works trips coming up.  I live in Las Vegas so I have access to some of the best salons.  I'd like to get in for an appt as soon as I can.  
Thank you, thank you, thank you!!