I thought I might shed some light being a hairdresser...

Bleaching or High Lift Tinting your hair on-scalp application I would avoid due to your body producing more heat than normal so you don't want the risk of heating up and irritating the scalp even more than what it does now I would recommend foiling your hair with bleach or high lift rather than on-scalp

Permanent and Semi-Permanent Are completely safe though if you are lightening your hair with the Permanent a few shades I would recommend a test patch acheiving the exact colour you want...

Semi-Permanent is completely safe just make sure that the hairdresser or box you are using is 100% ammonia free they all should be this but you will find a few colours which can be mixed with semi and permanent and contain ammonia...

And also if you are concerned let your hairdresser know before arriving that you are pregnant and are concerned and they will re-assure you or maybe even find another way around your usual colour I have soo many clients who are pregnant at the moment and have had their hair coloured from 6w onwards and ones who were pregnant and just given birth and had no dramas

The only thing not to do is Chemically Straighten your hair or Perm it as your hair produces more heat it will make the hair more brittle and these 2 products contain alot of chemicals and thats even when your breastfeeding you should avoid doing this aswell!!

Hope this helps feel free to pm me if any of you girls need to know anything regarding hair xxoo