Personally I wouldn't do it at all because of the known carcinogens in dyes. I don't know a whole lot about it but I do know that The American Cancer Society says that dyeing while preggo appears to "cause no
significant increase in risk for cancers". For them to tell me there is no "increased risk" or that it's "probably safe" is a little iffy.
However, if you look outside of the box and read cancer stories or read particularly about macrobiotics (promoting well-being) 9 times out of 10 you will read that hair dye is a huge no-no. Especially Black Hair dye, Or Red food dyes. (not that you'll be dyeing your hair with food coloring..lol)
Everything and anything is absorbed through the skin and into the blood stream.
I'd read around and then decide.

Theres some pretty useful info out there
I don't know anything about vegetable dyes either but If you feel safe with that I would try that instead of something permanent. IMO
I hope this didn't sound snotty or bossy...I just hate to be told one thing by doctors then a few weeks later be told their studies were wrong.
Take care mama..your babe is lucky to have you
