To color or not to color during pregnancy? My first bit of advice to Mom's to be is if you are uncomfortable with this procedure then you should probably not do it. My second bit of advice is highlights or lowlights. With highlights and/or lowlights we can change the color of your hair, cover grays, bring you back to your natural color...so many options. To apply any of these options I use foil. Each piece of colored hair is contained within a thin sheet of foil which keeps it off of the scalp. Since your hair is not a living organ the application of color within the foils does not enter your bloodstream. There is another risk; the fumes that are released during the processing of the color can be smelled at the shampoo bowl momentarily. Other stylists working within the salon could be preforming treatments such as a perm or straightening treatment which also release fumes.
However I have performed many color applications on myself and my clients during pregnancy and I have never seen any adverse side effects. I have also never heard any complaints from clients during or after their pregnancy. I would never suggest that a client who hasn't been receiving color consistently start a new routine. Go with your instinct and you will never feel bad about it.