I am a 5'10 transwoman weighing 165. What breast cup size would be best for me?

Your tissues are going to determine how big you can go at one sitting.  If you have some skin available, and it has the appropriate elasticity, a large implant could be possible. Forcing an implant into tissues that cannot  host that size is a good way to have implant malposition or an unnatural look.  That problem usually requires a second more complex and expensive surgery to fix BTW. FInd a surgeon who will measure and assess what your tissues can safely hold.

There are various factors like body measurements, body shape, and body frame to consider when it comes to choosing desired implant sizes in order to create the preferred fullness, profile, and shape of the breasts. An examination and fitting would have to be done to find out what best fits you.

I would recommend that you see a board-certified plastic surgeon who is a member of both ASPS & ASAPS and has plenty of experience in breast surgery. Go over your concerns with them and make sure above all, you walk out of there with several options and an idea of the pros and cons to each of them as well as realistic expectations.

I hope this helps and wish you all the best in your surgery and event. If it does, please take a moment to up vote this answer on the “respond” button on the top right.

Dear RSProfile3888249,
breast implant type and sizing selection is a complicated process and requires a detailed consultation that includes a discussion of your goals, a detailed examination, and a lengthy discussion. But the decision will always start and end with the patient. When it comes to sizing, we have all of our patients find 3 photos of their desired breast size. We ask for naked breast photos because clothing can obscure the true size (push up bras). Next, we consult with patients and go over the photos and take detailed breast measurements during a physical exam. Next, we using a sizing algorithm to determine a range of implants that will work based on the exam and the measurements.Lastly, during the operation, we use silicone sizers in the operating room to see how the size actually looks in the breast. We sit the patient up in the operating room, while asleep of course, and compare the sizer result with their desired look photos. If it is too small, we start the process over with a slightly larger implant. We don't stop until we get the perfect match.Of all of my breast augmentation patients, every one of them has been happy with their size due to this detailed and meticulous process. You don't want to invest time and money into a result that is either too big or too small.You should discuss your concerns with a board-certified plastic surgeon and make sure that your surgeon understands your goals.
Daniel Barrett, MD
Certified, American Board of Plastic Surgery
Member, American Society of Plastic Surgery
Member, American Society of Aesthetic Plastic Surgery

Every patient is different, as is their desired outcome. The size, profile, and shape of the implant is based on your desired breast size/shape/position, your chest wall measurements, and the soft tissue quality.  The implant decision should be based on a detailed discussion with equal input from both you and your surgeon.  During your consultation, make sure that you have adequate time with your surgeon and not just their patient coordinator or nurses. Make sure you specifically look at before and after pictures of real patients who have had this surgery performed by your surgeon and evaluate their results.   The most important aspect is to find a surgeon who understands your goals, and that you are comfortable with. In my practice, we use 3D imaging with Crisalix VR to help with the decision on implant size and profile. In my experience with Trans patients, I usually go with the largest implant that will fit their frame and accomplish the look they desire. You need to stretch the skin and soft tissue more than you think. Hope that helps some. Good luck.