However, Fran Dixon, creative colourist at Hari's Salon in London, is quick to point out that it's best to wait to refresh your roots until the first trimester's over to be extra safe. "Women usually wait until after the initial 12 weeks (or first trimester) of pregnancy when any potential risks are much lower," Dixon told Harper's Bazaar. If you're feeling anxious, "you can convert from all-over colors to highlights, so that the dye doesn't come into contact with the scalp," or switch to ammonia-free colors, she added.

If you're past the 12-week point, it's also important to be aware that being pregnant may cause your skin to react differently to chemicals than it usually would. Shannon Lewis, color director at Neville Hair & Beauty, and Anna Short, color director at Daniel Galvin, warn that it can even change the final color and smell of the hair dye. Always be sure to do a patch test before the treatment begins, they told Harper's Bazaar, and if you experience any irritation, do not proceed. Above all else, it's a good idea to ask your doctor, just to be on the safe side.