During pregnancy, it's recommended to be cautious with chemicals, including hair dye. While studies have not conclusively shown that hair dye is harmful, the effects of the chemicals on the developing fetus during the first trimester remain uncertain. Experts advise to limit exposure to chemical hair products, especially in the early stages of pregnancy.

If you choose to dye your hair while pregnant, consider using highlights or semi-permanent dyes, which have less exposure to the scalp. It's also advisable to dye your hair in a well-ventilated area and to avoid using hair dyes that contain ammonia or other harsh chemicals. Consulting with your healthcare provider can provide personalized advice based on your specific situation.