Info from pregnancy.org... "many experts now contend the dyes are most likely safe and that women needn't be afraid to color their world during pregnancy.
That said, don't be surprised if your doctor still suggests you approach hair coloring with caution.
Because the dye is absorbed through the scalp and into the body (it can be identified in urine) some medical experts are hesitant to give carte blanche to hair coloring during all three trimesters. Often, many physicians advise holding off coloring hair with permanent dyes during the first trimester when your baby is undergoing important neurological developments."
Hope that helps!
