Can You Color Your Hair While Pregnant?
Yes, it is generally safe to color your hair while pregnant.
More Info: According to an article published in the Canadian Family Physician there has been no clinical evidence to date that dying hair is toxic. (See link and cited references for full details.) Many women opt to forgo any activity that involves chemicals during pregnancy. Of course pregnant women should always consult a physician before undertaking any activity.
Koren MD FRCPC, Giddeon. "Hair Care During Pregnancy." Can Fam Physician April.42 (1996): 625-626. National Center for Biotechnology Information. Web. 1 June 2010.
Current Research Findings
Only a small amount of dye is absorbed through the scalp and with such a minute quantity getting into the system, very little of that is presented to the developing baby. Furthermore, there are countless women who have applied dye to their hair during pregnancy without any identified accounts of adverse effects on the baby. With that said, not many studies exist in the use of hair dye during human pregnancy. The studies done on animal pregnancies showed no significant alteration in the development of fetuses with doses 100 times greater than a typical human use of a single product. It should be noted that there are a variety of chemicals used in hair dyes and manufacturers change formulations regularly so studies are based on doses existing at the particular time of the formula's evaluation. Also, frequency of application, amount of contact with dyes and timing of use during pregnancy are significant factors to consider.
To be safe, the FDA recommends that when coloring hair one should wear gloves to minimize skin surface contact; not leave the dye on for an extended period; and wash the scalp well after the application of dyes. Finally, it is important to consult with a health care provider for guidance on the subject.