I Am 5'8" 140lbs, 36DD-36DDD, my Measurements Are 34-28-35, Would It Be Difficult to Go to a B Cup?

Congratulations on your decision to proceed with breast reduction surgery; it is one of the most patient pleasing operations we perform.
Before undergoing the breast reduction procedure it will be very important to communicate your size goals with your surgeon.  Most patients wish to achieve a 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. 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.
Yes, it is possible to reduce the breasts size very significantly.  The concern with the amount of tissue removed is related to blood flow to the remaining tissue;  if too much tissue is removed in one operation the blood flow to the remaining tissue (including nipple/areola)  may be compromised.   Part of the tissue that is left in place is called the “pedicle"; this segment of tissue is responsible for delivering the blood supply to the nipple/areola tissue. If the pedicle is made too small (in the effort to reduce the breasts as much as possible)  then patient will likely have problems with tissue survival.  
The other concern with overly aggressive breast reduction surgery is patient dissatisfaction  afterwards.  It is not unusual for patients who have lived with very large breasts to want to have as much as possible removed. Care must be taken to be judicious in this removal to avoid an outcome where the breasts  are too small in relation (proportionately) to the patient's other body parts.  Again, it is not uncommon, for patients'  breasts to become smaller ( after the breast reduction procedure) with time and/or weight loss-  breast augmentation may become necessary to achieve the patient size goals.
I hope this helps.

Hello,

Thank you for your question.  How small a breast can be after a breast reduction depends on a number of factors but ultimately are related to the need to maintain blood supply to the areola and the remaining breast tissue and skin.  A triple-D breast may be a little difficult to reduce to a B cup breast and still provide a nice shape.  It will be close but what is important to remember is that whether you are a B cup or a C cup you will still be very happy as long as your breasts heal well and have a nice shape.

All the best,

Dr Remus Repta