You may already know that a bra cup size varies according to manufacturers. What is right for you depends on many different factors.
Some of the important factors in determining your postoperative size:
1. Patients desires are of primary importance and this is discussed in preoperative consultation. Some women are really looking for a lift and would like insurance to cover what is considered a cosmetic operation. Insurance companies may use many different parameters. One of the primary issues is grams of breast tissue respected and this is often determined by height, weight or B.M.I. If enough breast tissues is not removed then an insurance company could argue that it was a cosmetic operation. Some ladies have asked for essentially a mastectomy but In my opinion many plastic surgeons would not do such a surgery. We can always take more but we cannot easily add your breast tissue. Generally, women want freedom from symptoms and this normally results in an attractive postoperative appearance that is proportional to your body
2. Nipple in relation to inframammary fold. In the ideal setting the nipple should not be below the fold at the bottom of the breast. We typically use the inframammary fold as a landmark for the repositioning of the nipple during surgery. The midpoint of the humerus ( bone of the upper arm) is considered to be another ideal location for your nipple. Nipple location is a critical part of any breast surgery because their location on the breast may enhance but also distract from an otherwise good result.
3. Distance from collar bone to nipple of over 40cm a limit for pedicled techniques. Longer distances would need a free nipple graft. This requires complete removal of the nipple and similar to a skin graft placement on a viable area of breast. This is now considered more of precaution with surgeons having success with pedicles of greater than 40cm. Some surgeons may still stick to this rule.
4. Remember that your upper half is giving a balance to your lower half. I tell women that are about to have a reduction that I did not make their stomach or hips larger. The reduction of the upper half gives the illusion of the hips and lower torso increasing in size. So patients may complain that something was added during surgery to their lower half.
These things I learned as a plastic surgery resident and they hold true today. I thank everyone who shared a piece of knowledge that stick with me after over 10 years.
To answer your question, the size is what you and the surgeon can agree upon. There is no magic device that can give you the exact cup size. Just the trust that we are honored to hold fulfill your desires to the best of our ability.