hair dye situation

Can I bleach my hair pregnant? Well I think that’s what I have to do, I’ve been dying my hair black for about a year and it kinda stained my hair and I wanna go back to my natural blonde it was so pretty and I loved it was just bored and changed it up a little and kept doing it and it stained my hair. Would I have to bleach it or is it something else and if something else what is it and is it safe for me to do 23 weeks pregnant?