As you have probably heard already this is more about "communications" between you and your BCPS. Very difficult to correlate numbers and a "cup" size. This really a concept more than an exact measurement. All of my Cs come back from a well know store I will not name as Ds or DDs. Speak slowly with your doctor. Hope this helps.
Insurance companies have their methods to determine how much breast tissue should be removed, though we feel as your surgeon we should determine what you need for the best result for your comfort and your goal after breast reduction. Most will wear a D cup after reduction because of the base width of the breast however a smaller cup, perhaps a C is possible. Be sure to discuss what you would like to be after reduction.
your new size will be determined by the overall breast shape and size. Cup sizes are difficult to predict because of the variability of bra sizes
Thank you for the question and congratulations on your decision to proceed with breast reduction surgery; this operation tends to be one of the most patient pleasing operations we perform.
There is no direct correlation between the amount of tissue removed and the ultimate cup size that a patient will wear after breast reduction surgery.
Before undergoing the breast reduction procedure it will be very important to communicate your size goals with your surgeon (who you should choose very carefully). Most patients wish to achieve enough of a reduction to help with their symptoms while remaining proportionate with the remainder of their torso.
With the goal of improving communication with my patients I find the use of photographs of “goal” pictures (and breasts that are too big or too small) very helpful. For example, I have found that the use of words such as “natural” or “B or C cup” means different things to different people and therefore prove unhelpful. Also, as you know, cup size varies depending on who makes the bra; therefore, discussing desired cup size may also be inaccurate.
Once you have communicated your goals carefully, your plastic surgeon will be able to provide you with an estimation of how much tissue will need to be removed, in order to achieve your desired outcome.
Best wishes with your breast reduction procedure; hopefully you will be very pleased with the outcome of the procedure performed.
You are small in size with relatively large breasts by your description. One would expect that even after a reduction of 420 grams, your breast will still be a C-D cup. Of course, everyone measures breast cup size differently. Just make sure your plastic surgeon understands your wishes prior to heading into the OR.Good luck!