You're completely fine as long as you're in a ventilated space.
I highlighted and colored my hair during my entire pregnancy every 5 weeks like clockwork with my doctor's blessing! Hair treatments in today's world are not like those in the past. While always safest to ask your own doctor, this is not generally a worry. good luck
Ladies thank you very much for your comments it make me feel better and less worrying.
I colored my hair when pregnant in my second trimester and was fine :) You're not ingesting it, it's not entering your blood stream, it's just tinting your hair a different color lol I worried a lot about it too but it's safe as long as you don't mind the fumes with your sensitive pregnant nose!
Doesn't matter what trimester you're in, you can color it. One way to look at it, the hair dressers never take off work when they're pregnant for coloring hair !
I had the same question while I was pregnant. You should be alright because you are in your 2nd trimester. Just don't do it often if you do want to continue colouring your hair do it in a open area where air can come inside and try to do more highlights then actually doing the whole head where the color can touch the skin.