Women want to look beautiful during pregnancy or even after giving birth. The first thing they want to fix is the hair.
I love to color my hair but stopped when I was pregnant with Elijah. Three months after giving birth, I asked my cousin to put some hair color at the tip of my hair. I am dying to color my hair red again and afraid at the same time that it would cause bad effect on my milk that is why I decided not to put any hair color near my scalp. Nothing happened since then and I guess it’s okay to use hair treatment as long as the chemicals used are not that harsh. Better ask your doctor if in doubt, professional salons won’t offer a service if they are unsure about the products they are using also they have to keep their reputation in good name.
There is no known negative effects of hair treatment during breastfeeding. Chemicals used in hair straightening, coloring and highlighting are not absorbed through the scalp so there is no chance that it will enter the bloodstream.
Ask your doctor and a hair exert regarding this issue if you are in doubt. I tried hair coloring and hair relax while I am still breastfeeding and see no negative effects at all.