However, research into hair dyeing during pregnancy is pretty limited, so to be on the safe side, some experts suggest staying off the dye until you reach 12 weeks, when the risk of chemical substances harming your growing baby is much lower.
But for the dyers among us, that can be tricky news to digest as roots come through or that pesky patch of grey starts its regular six week regrowth.
If you're worried, consult your midwife or GP for advice before you reach for the disposable gloves.
If you're dyeing your hair at home, there are several safety procedures to think about during pregnancy – and all are really straightforward:
Leave the dye on for the minimum time.
Dye your hair in a well-ventilated room.
Rinse your scalp once the dye is applied.
If you do want to avoid your usual dying sessions when pregnant, there are a couple of good alternatives. Highlighting your hair (which only puts dye onto strands of your hair) reduces any risks as the chemicals are not absorbed at all by your scalp and bloodstream. Semi-permanent vegetable dyes, including henna, are other good alternatives.
If you're a salon regular, ask your colourist for advice and have a consultation before you go in for your appointment.
Overall, it's important you feel happy and comfortable during your pregnancy. If dyeing your hair will make you worry, ask your midwife as many silly questions as you like – he or she will have heard them all before.
If the idea of dyeing your hair is likely to worry you regardless of the information and advice you receive, give it a miss – and have a post-birth treat to look forward to instead.
For more information, visit NHS Choices.