I've heard you can dye your hair, but not bleach it. i bleach mine as well my roots look TERRIBLE it's going to be hell getting it back to platinum blonde lol but I'd rather not take the chance personally. I only have 55 days left, and I've lived this long without coloring it lol.
Im a cosmetologist and its safe after the first trimester just know that all the new hormones in your body it might not turn out like it always does... I turned a ladies hair green on accident but had been using the same color on her for years .. sometimes it will cause the dye to process faster.. just keep a good eye on it and you and your baby will be fine!
I have heard not to color your hair at all while pregnant
They say not to especially in your first trimester. My sister owns a hair salon and worked through both pregnancies. Her doc said it was fine.