Orange Roots? How?!

I had a daughter 6 months ago. I am not breastfeeding. Ever since i became pregnant, every time i dye my hair, the ends take to the color i chose, but the roots turn orange! This has happened several times and with 3 different shades that are very close to my normal color (i don't go drastic, never did). And its just gettting worse, not better. I have dyed it myself at home and also have gone to professional salons, and still the same results. What is causing this problem? I cannot fix it, because it does not fade and redying seems to not be a solution, obviously. Please help! No one knows what is wrong with me! Not even the professionals!