any suggestions?

So, my natural hair color is like light brown and well my roots are now starting to show since I haven't dyed my hair in over 2months... I've had black hair since two years ago and always dye it black.(because of my grey hairs) lol but recently I've wanted to just go back to my natural color so basically just dying it brown but I wanted to know if anyone on here has changed their hair color while pregnant? I'm 32 weeks and would like to not look like a granny with a head full of grey hairs while giving birth my first time at 19! Lol so any suggestions on how to lighten my hair or something of that nature?