How do doctors decide what size implant to use during breast augmentation surgery?

As you see from answers submitted, there is no one way to determine size, so each surgeon will tell you how he or she selects.My approach is to apply four criteria, all equally important.  First, I listen to what the woman wants.  Women choosing breast augmentation generally have more or less specific ideas about the breasts and body they desire.  Listening involves learning about the woman's lifestyle, her activity level, and considering her stage of life. Breasts must also be considered within the context of other facial and body features.  In my opinion, larger breasts can be used to visually narrow a woman's waist, and complement other attributes, such as a beautiful face.  My goal is to get as much "mileage" out of the implants as possible.  Her individual aesthetic ideal must be considered:  Some women want large implants that look like implants, round and high.  Others want a subtle enhancement, unrecognizable as augmentation, naturally adding gentle feminine curvature without specifically drawing attention.  The second criteria is base width of existing breast.  The implant must be about as wide as her breast so there's not a central gap between the breasts, and so they don't hang out to the sides too much (unless she wants "side boob").  Angulation of ribs must be considered in the calculation of implant width as well.Next (third factor) is how much breast she's starting out with.  If she is very flat chested, a higher profile implant will be needed to achieve her goals.  If she's starting with a full B or small C, then a smaller implant will be needed to reach her desired size.  Fourth is the skin envelope.  If she has had children, especially multiple children, nursed, and has a loose skin envelope, a larger implant can be accommodated.  If her skin envelope is tight, it is more difficult to use an ultra-high (full) profile prosthesis without stretching the skin and connective tissue, a process that may be irreversible.  Breast augmentation should be explained within the framework of her multi-faceted life.  It is helpful, I believe, for women to understand changes they can expect over time.At no point did I mention implant volume, because it is meaningless.  A 400cc implant can be wide and flat or it can be narrow and globular.  Volume is immaterial relative to dimensions.  Beyond size, the texture of the implant, surface, positioning, and approach for placement affect the final outcome considerably.

It is very difficult to determine the exact size and shape implant you will require to best match your ideal breast image without an examination by a board certified plastic surgeon. Not just any board certified plastic surgeon, but one with many years of frequently performing breast augmentation surgery including different approaches, techniques and implant choices. This is because several measurements not to mention your breast characteristics are needed to determine the optimal implant size to obtain your goals. Without knowing these dimensions it would be difficult to make this determination. For example, the existing base width of your breast will determine, in many cases, the maximal volume per implant profile that you can accommodate. To illustrate; a 100 cc difference may make a significant difference with a narrow base width breast, but much less of a difference if you have a wide chest wall and wide breast “foot print”. Therefore, just because your friend may have a great result with let’s say a 350 cc implant to make her go from a “A” cup to a “C” cup size does not mean that you will have the same result with the same size implant. . Further simply placing implants in a bra to determine the size best for you is not always accurate as the bra often distorts the size, is dependent on the pressure the bra places plus the implant is outside your breast and not under it among other variables. Computer software morphing programs that automatically determine the best implant size can be helpful in some but not all cases (e.g. doesn’t work well in my experience with existing implants, sagging or asymmetric breasts). Using “want to be” photos however are useful if simply provided to the surgeon as I will further explain in the below link.#breastaugmentation#findingtherightsize#BA

At
size 32 or 34 each 100 cc’s of implant corresponds to 1 cup size change.At size 36 or 38 each 200 cc’s of implant
corresponds to 1 cup size change.From
this, you can compute the volume required to achieve your desired goal.I always recommend small round textured
silicone gel implants placed retro-pectoral since they look and feel more
natural, are more stable, less likely to ripple or have complications needing
revision.Implant profile is irrelevant
in the retro-pectoral position since the muscle compresses it.Best Wishes,Gary Horndeski, M.D.