id say d to dd because of the swelling! but i just got a couple macoms so all you need to measure is your back size, the one sports bra i got is a 32c which i think will be okay for me after the swelling has gone down, best person to ask is your surgeon or pc though! better to buy 1 or 2 now and then the others after ur ba so u can see which to buy, or just keep the tags on and take back what doesnt fit xx