5'4, 115 lbs - 375cc or 400cc?

Thank you for your question.  Choosing an implant size is an exciting part of the breast augmentation procedure, but also difficult because of the sheer number of choices.  Though surgeons can't promise a particular cup size with surgery, trying on the implants is a great method to identify the right cc size for you.  Depending on your frame, and the profile and style of implant, 25cc can make a difference in how you perceive yourself in and out of clothing.  Be sure to communicate your desired appearance with your surgeon, they can help guide you, and can provide reassurance that the 375cc implant that you liked will get you to your goal outcome.

Thank you for the question. Depending on a specific woman's anatomy and goals ( in regards to outcome achieved with breast augmentation surgery), 25 cc may or may not make a “big difference”. For example, for a petite patient striving to achieve a relatively “modest” outcome, 25 cc of a larger volume implant may be noticeable.Given your questions/concerns, I would suggest that you spend additional time communicating your goals with your plastic surgeon,  preferably prior to the day of surgery. Generally speaking, the best online advice I can give to ladies who are considering breast augmentation surgery (regarding breast implant type/size/profile selection) is:
1. Concentrate on choosing your plastic surgeon carefully. Concentrate on appropriate training, certification, and the ability of the plastic surgeon to achieve the results you are looking for. Ask to see lots of examples of his/her work.
2. Have a full discussion and communication regarding your desired goals with your plastic surgeon. This communication will be critical in determining breast implant size/type/profile will most likely help achieve your goals.
In my practice, the use of photographs of “goal” pictures (and breasts that are too big or too small) is very helpful. I have found that the use of words such as “natural” or "B or C cup" etc means different things to different people and therefore prove unhelpful.
Also, as you know, cup size varies depending on him who makes the bra; therefore, discussing desired cup size may also be inaccurate.
3. Once you feel you have communicated your goals clearly, allow your plastic surgeon to use his/her years of experience/judgment to choose the breast implant size/profile that will best meet your goals. Again, in my practice, this decision is usually made during surgery ( after the use of temporary intraoperative sizers).
I hope this, and the attached link (dedicated to breast augmentation surgery concerns), helps. Best wishes.