I read a pregnancy article about it and they suggested not dying hair while preg. Especially bleaching it, I would think from the fumes that come off of the bleaching kit. I wont breath anything, I avoid touching anything poison. I take only tylenol. Your hair usually gets thicker and grows like crazy when pregnant. Doesnt fall out after either--as far as I know. Mine didnt. The healthiest mine has ever been was when I was pregnant.