I am 5'3" and 129 lbs with 36DD/36DDD breasts. I am having a breast reduction. What size could I potentially go down to?

A breast reduction can decrease your breast size to almost any degree.  You can go from a DDD or GG down to almost any smaller size.  Your choice depends on just what you think will make you comfortable physically and mentally.  You can be reduced down to an A cup size or just to the next smaller size, say from a D to a C cup size.  Consider your overall frame and stature, your lifestyle, and how you would like to look in clothing.  I have had patients request the whole range of sizes depending on how they answer the criteria I mentioned above.  Good luck.

Thank you for your questions. Congrats on your upcoming procedure! You need to discuss your goals with your surgeon for sure. That being said, the goal of a reduction is not to achieve a certain cup size, but to end up with something smaller that fits your frame well but relieves your symptoms. There is not really any gram cup size equivalent, but for a rough estimate, usually plan on around 150-200 grams of tissue removed for a cup size. So if the tissue removed is going to be 300-350 grams, you are probably looking at a reduction of 1.5-2.5 cup sizes. Hope this helps!Dallas R. Buchanan, MD, FACSOwner & Board-Certified Plastic SurgeonVIVIFY plastic surgery

There is no "right answer"; patient preferences play a very large role when it comes to determining final size  achieved with breast reduction surgery.
My best advice: select your plastic surgeon carefully. Make sure that he/she has significant experience achieving the types of outcomes you will be pleased with.
Before undergoing the breast reduction procedure it will be very important to communicate your size goals with your surgeon (who you should choose very carefully). 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.  For example, 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. 
Once you have communicated your goals carefully, your plastic surgeon will be able to provide you with an estimation of how much tissue will need to be removed, in order to achieve your desired outcome.
Best wishes

Thanks for your question. If the plan to take out 300cc each side so probably you would go very close to C cup.I think this is a reasonable size to fit your frame. Cup size varies from one brand to another. But roughly, C cup. would look natural on your chest. 

Thank you for your question. Breast reduction is one of my favorite surgeries. The effects can be felt immediately and it can really change a woman's view of the world.  Cup sizes are hard to predict, partly because they vary from bra maker to bra maker. I never promise a size. I shoot for, smaller, lighter, uplifted and youthful and proportional. The goal is to keep you still looking like a girl!  Making someone too small creates a similar problem of disproportion but now too small. Consult with a Board certified plastic surgeon experienced in  breast reduction surgery and express your concerns. Look at before and after pics and make sure you feel like he or she is listening to you and understands your concerns and expectations. Best wishes,Dr. Morrissey