Hi there ~
I understand your concern about itchiness in your areoli. However you do not need to be concerned as it is not uncommon during pregnancy
to have this condition. If you have any issues with your brassiere during pregnancy, please make sure that you change them since breast enlargement is also the norm during pregnancy. I believe that you should consult an obstetrician and read up about normal pregnancy as your pregnancy progresses. All the very best.
Take care of yourself and have a lovely day!