my cousin dyed her hair in her second semester in a well ventilated area (outside) and she had a healthy baby girl on july 3rd. like they^^^ said ask your dr just to be sure
Like babyturnip said, ask your doctor just to be sure because every doctor and every pregnancy is different. In my hair school, we typically have clients wait til after the first trimester to do an all over color or root touch up because the chemicals do go directly on the scalp (although the amount of chemicals absorbed through the skin is very very minut). High lights are ok anytime because the color does not actually come on contact with your skin or scalp. It only coats the hair in the foils. Again check with your doctor to be sure, but my guess is he will give you a green light :)
Well dying ur hair is not good for ur hair or scalp to beginning with but again its probably not recommended bevause of the chemicals but i know lots of mommas who do it. U would really just ask ur dr. Every dr are different but just a quick phone call is all u need and ur mind will be at ease