My BWD is 13.5 and 14. If I choose an implant that is 13, will this leave me with an unnatural gap?

Hello and thanks for your question.There are several factors that are very important in determing the shape:-Pre-operative shape-Pre-operative dimension and diameter of the breast-The amount and quality of breast tissue and skin-Implant size, shape and profile-Careful dissection of the pocketIn our office, we use actual implant in the pre-operative period to determine the size.Best Wishes,Dr Sajjadian

Although base diameter of your breast implant is an important measurement the surgical technique that your plastic surgeon will use to create your breast implant pocket is equally important to avoid a large space between your breasts.Generally speaking and anecdotal estimate is that 200 cc of breast implant will enlarge the breast by 1 cup size from the bra that you are currently wearing.  The implant sizes that you have chosen will likely create the appearance that you want.For more information on choosing breast implant size please read the following link:

Thank you for the question. Careful breast implant pocket dissection and careful selection of breast implant size/profile will be necessary to address your concerns about the space between the breasts. Of course, there may be some anatomic limitations as to how closely the breast implants can be placed, without risking breast implant malposition complications. In regards to specific size/profile of breast implant, despite good intentions, online consultants will not be able to provide you  with  meaningful specific advice.  Ultimately, in person consultation with well experienced board-certified plastic surgeons will be necessary. Careful measurements, dimensional planning, and careful communication will be key.
Generally speaking, the best online advice I can give to ladies who are considering  breast augmentation surgery ( regarding breast implant 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're looking for. Ask to see lots of examples of his/her work.  
2.  Again, have a full discussion and communication regarding your desired goals with your plastic surgeon. This communication will be critical in determining which operation and/or 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 "small D cup" or "fake" etc 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.  The use of computer imaging may be very helpful during this communication phase.
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.  The use of temporary intraoperative sizers, viewing the patient's breasts in the upright and supine position, are very helpful during the breast implant selection process.
I hope this, and the attached link, helps.