There is no absolute answer to this question. But ask your doctor/Hairstylist for their opinion. Consider waiting to color your hair until the second trimester, when your developing baby is less vulnerable. Also, rather than using an all-over hair color, consider a process like streaking, highlighting, painting, or frosting, in which the chemicals have little or no contact with your scalp. (Any hair-coloring agents absorbed into your system would come through your skin, not through your hair shaft.)
If you do choose to color your own hair, wear gloves and work in a well-ventilated space to minimize your exposure to the chemicals used in the coloring process. Don't leave the dye on any longer than necessary, and thoroughly rinse your scalp at the end of the process.
he biggest concern for pregnant women is the smell of he chemicals, and how long you are in contact with such chemicals....Happy Coloring!