You need a lift if your nipples are below the level of your inframammary creases!
If your nipples are facing forward and are above the level of your inframammary crease, then you may obtain a nice result with augmentation alone, but may need large enough implant volume to adequately "fill" your loose breast skin. You should first have a desired size in mind, rather than asking a surgeon what size you should be. Then, an experienced plastic surgeon can determine by examination, careful measurement of your chest and breast dimensions, and talking with you about your desired outcome, just what size and profile of implants will work best to fulfill your goals in accordance with your anatomic requirements (with or without a breast lift).
You should read my article (on my "About" page) "What is the Right Breast Implant Size for You?" for more information about this critical topic. You can also read much more information at my website link below.
Breast Enhancement Surgery
Sounds like you are petite with a wide torso, in that cases you will need to have an accurate measurement of your breast width because if you pick too wide the implamts will be easilly visible
Sizing of implants in small framed woman.
It is not possible to give you a fair answer without an exam, measurements, and an assessment of what the outcome you might want. There are many variables in choosing an implant size. Find some photos that you like and take them with you to your board certified plastic surgeon. Best to see a few of them. Remember that you may need a lift. Also remember to have reasonable expectations.
What size breast implants?
You need to decide what size you would like to achieve. You can try different bras at home with different volumes of rice in a pair of tights (stockings) to work out a rough volume you like. Your Plastic Surgeon will then be able to determine from your measurements of your breasts and chest the optimum size. Whether or not you need an uplift will depend on how much drooping you have and the volume of implants you decide. If you nipples are pointing to your toes - you will need an uplift. But if they are pointing straight ahead but just at your breast crease then just an implant will restore your fullness. As a guide - 120- 130cc will give you 1 cup size increase. Good luck.
Implant size recommendations can't be made accurately via the internet
Accurate breast implant sizing can't be done over the internet just based on a few measurements. Photos could be more helpful but still would not allow for precise recommendations. You should be evaluated by your local plastic surgeon who would then also discuss the relevant factors which would allow you to make an appropriate decision which would include more than just the implant size.
Choosing breast implant size
An actual consult with a breast exam would be the best way to answer your question. One must first determine if you have adequate tissue coverage and then degree of ptosis or position of your nipples. The quality and amount of breast tissue will determine the optimal volume of the implants and the position of your nipples will tell what the best type of lift is. You could then try different sizers and choose a specific volume or size for the implant.
The Optimal Breast Implant Size
Implant sizing is an process that is individualized for each patient. There are many factors in determining implant size. These factors include, the patient's breast size, breast measurements, skin laxity or stretch, height, weight, etc. During your examination with your plastic surgeon, you and your surgeon can determine what implant size is optimal. For more information, see drmezrow.com
What size breast implants
You really dont give enough information to answer the question. There are many variables which must be considered. be sure you get a couple of consults and that what the surgeon tells you makes sense to you. At that point post your pictures here and then you may get better advise. good luck
Breast augmentation together with breast lift
Breasts are made up of variable quantities of fat & breast gland. Although in general younger women have a greater percentage gland & older women have a greater percentage fat it is not possible for even the educated eye to accurately estimate the percentage composition just by looking at the breast. Because fat is more compressible than gland tissue 2 women with different breast composition (fat vs. gland) can have the same size breasts before surgery & have the same sized breast implants placed but end up with different sized breasts. The one with a greater percentage of gland tissue in the breast will be larger.
Without photos or a face to face examination it is impossible to say what would be best in your case. Given your height and weight it would be quite unusual for you to have a breast base width diameter of 16.5cm. The average for a woman in the upper 5foot height range is 13cm.
My response to your question/post does not represent formal medical advice or constitute a doctor patient relationship. You need to consult with i.e. personally see a board certified plastic surgeon in order to receive a formal evaluation and develop a doctor patient relationship.
To properly fit implants, a full examination is required. It's not just about the breast width (and 16.5cm seems very wide for someone 5' and 120lbs), although that is an important measurement. Choosing implants when also performing a breast lift involves more care than an augmentation alone. I recommend that you see a few Board Certified Plastic Surgeons prior to making your choice and go with the one that makes the most sense to you.