It's best to talk to a bra specialist about this. The women in maternity stores are really helpful
At less 1 size up I went 2 to be safe
You don't know what size to get. Go with the safe option and buy a couple sports bra type nursing bras for now and then buy fitted ones after your milk comes in. When my milk came in I went from a 34B to a 36E overnight. No way would I have guessed the right size, and there's no way someone else would have been able to pinpoint the right size for me either. Some women get much bigger right away and some women barely get bigger at all.
I haven't gotten bigger at all. Baby girl is 4 weeks and I'm producing a good amount of milk. I'm currently breastfeeding and exclusively pumping. After 2-3 days of nursing her from the very get go...my nipples were so sore and cracked even with a good latch per the LC ! So yea...ive kinda stuck with pumping exclusively. But yea... I just went up a size and only bought 2 bras to begin with. Now that I know I probably won't get bigger I'll definitely be buying a padded nursing bra because I tell you my nipples get hard randomly all the time and you can see them clearly through any