I called my Dr and got it ok with them before I dyed my hair. I lightened it first and then darkened it. They say that there is not enough chemicals are absorbed into you body to harm the baby. If anytj injng call your dr to get the ok. I've had 3 other kids and dyed my hair with all of them.
You're not suppose to do anything to your hair till 13 weeks. It can be harmful to the baby if you dye your hair in your first trimester.