hair dye whilst pregnant

Sarah • TTC since April 2016. MMC #1 Sept `16 MMC #2 Jan `17 Ectopic and Tube Removed Nov ‘17
Hi folks!
I'm 6 weeks pregnant. I currently have blonde hair that I upkeep with peroxide highlights however I have not had it done in a while therefore roots are on their way! So I would like to dye it brown now so I don't have to upkeep the peroxide highlights whilst pregnant. Plus if it's brown I won't have to dye it again for the whole pregnancy. Has anyone dyed their hair whilst pregnant with no ill effects? 
Thank you :) xxxx