Why can't doctors go from D cup to A cup? It bothers me that most breast reductions almost never go small enough.

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. 
My best advice:  seek consultation with board-certified plastic surgeons who can demonstrate significant experience achieving the types of outcomes you will be pleased with. This careful selection of plastic surgeon will be the most important decision you make.
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.  I suggest that you do not communicate your goals in terms of achieving a specific cup size. For example, a “A cup” may mean different things to different people and therefore may be a source of miscommunication. In my practice, I ask patients to communicate their goals with the help of goal photographs.
 
I hope this helps.  Best wishes.

Hi.  It basically comes down to blood supply.  For the nipple to be repositioned it needs to be maintained on a block of tissue that we refer to as the pedicle.  That then allows the nipple to be shifted upwards, thus giving a breast lift at the same time as making the breasts smaller.  If that pedicle is too small, then there will be an inadequate and poor blood supply to the nipple which can actually result in the nipple dying (either partially or fully).  As such, the pedicle is designed to try and maximize vascularity or blood supply to the nipple as well as a good nerve supply to the nipple, but also try to reduce the size of the breast to what the patient desires.I would recommend consulting with a board-certified plastic surgeon with good experience in this area to help guide you through this process.Good luck and take care, Dr. Howell

Good question. Often women with very large breasts are so fed up with them that they even say "I just want them off." The surgeon has two goals, to reduce the breast size adequately but still end up with an attractive breast. It is really not possible to achieve an attractive A cup breast after a breast reduction because the breast base starts off so large the breasts would look very flat, not very pretty. Usually I tell patients that a C-cup is a good goal to remove the weight and still look good. But ultimately it is the patient's decision, and I have taken breasts down to almost flat in women who tell me that is what they want.