Can’t decide on cc size. I’m thinking 420cc or 430cc, high profile and under the muscle. Thoughts?

Breast implant volume choice is only one factor because that volume can come in all sorts of shapes which does impact the final result. Since a high profile implant was chosen and the volume range has been narrowed it seems like you have made your mind up because there is little difference between a 420 and 430 high profile implant. I would recommend that your goals meet those of your plastic surgeon and 3D imaging could help reinforce this.

Hello and thank you for your question.  The
best advice you can receive is from an in-person consultation.  The size, profile, and shape of the
implant is based on your desired breast size/shape, your chest wall
measurements, and soft tissue quality.  This decision should
be based on a detailed discussion with equal input from both you
and your surgeon.   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 you are comfortable with. I recommend
that you seek consultation with a qualified board-certified plastic surgeon who
can evaluate you in person.
Best wishes and good luck.
Richard G. Reish, M.D.  FACS
Harvard-trained plastic surgeon

There is not much difference between the sizes you mention...around a shot glass worth.  The bigger issue is high profile versus medium or extra high.  Personally I find that saline implants ripple more and are a lot firmer.  You may want to look into that further.Good luck!

Thank-you for your question.
Choosing the correct breast implants may seem overwhelming due to the options available for implant material (silicone or saline), placement (under or over the muscle), implant size and shape. Treatment plans are individualized for each patient based on findings during the consultation to meet your goals. 
Selecting the correct implant size and shape is among the most important decisions in a successful breast augmentation procedure. Placement of the identical implant will not produce the same results in all patients due to differences in:
1.Dimensions of the breast 
2.Diameter of the chest 
3.Volume of breast tissue 
4. Height and weight 
5. Breast shape, including breast ptosis and asymmetry
I rely on 3 methods to advise my patients:
1. Dimensional planning 
2. Gel implant sizing 
3. 3-Dimensional Vectra imageing system.
At the time of consultation, measurements are taken allowing for dimensional planning to select the implant which best fits the base diameter of the breast. Gel implant sizing is performed to allow you to visualize augmentation the with the various sized implants. Vectra 3-D imaging has been a very important method in my practice in selecting the correct implant size and shape as it allows you to see what you will look like following augmentation with any of the available implants. I would recommend a consultation with a Board Certified Plastic SurgeonBest regards, Andrew Lyos MD, FACS

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

Patients often think in terms of cup size when considering augmentation. Unfortunately, devices are sized in terms of milliliters (cc) of volume. This can lead to some confusion when sizing. Additionally, it is important to remember that cup size itself is not standardized with variations from one manufacturer to another. Unfortunately, as many women can attest their cup size in an industry leader such as VS is not necessarily transferable to another brand.
Another point which is often under appreciated is that of anatomy and starting point. Any implant will add volume to the volume which is already present. The implant is additive. A particular volume will not necessarily confer the same cup size to different patients (often times it will not even confer the same cup size to different breasts in the same individual...remember they are "sisters" not "twins"). 
A general rule of thumb is that 125cc can represent somewhere between 1/2 to a full cup size increase. Smaller volume differentials (25-50cc) are typically less consequential representing a volume change of less than a shot glass. However, I have found these numbers, at least anecdotally, to be of little help. Patients often present with notions/goals which do not correlate with these sorts of sterile volumetric assessments.
When sizing patients, there are a number of useful tools including:
-3D imaging (has the added benefit of offering a volumetric analysis of the pre-operative breast)
-Breast sizers (rice bags)
-Goal photos
I also recommend that patients commit to a particular look rather than a cup size. Once a patient settles on a look that pleases them the overall cup size increase becomes less relevant.The key to obtaining a natural result is to stay within the parameters defined by your BWD. This will ensure that you avoid the dreaded "fake" look. 
With regards to your specific questions, I would not stress over a 10 cc differential. This amounts to a few teaspoons. This is unlikely to make a significant difference in your result.
In smaller framed individuals seeking a "natural look," conservative sizing is best. Small individuals rarely have exceedingly large breasts. Over-sizing is a hallmark of a "fake" or "augmented" look.  A higher profile implant will provide greater volume at the same BWD. There is a trade off of subtlety for gains in volume and projection. In my practice these devices are reserved for smaller framed individuals.
As always, discuss your concerns with a board certified plastic surgeon (ABPS).

There is a minor difference between 420 and 430, too small to be of concern.   The implants have a range of fill volumes. For example the recommended range for a 380 cc implant is 380 to 420 and the 420 implant 420 to 460.   The implant is firmer with the nigher volume, so a 380 implant filled to 420 will feel firmer than a 420 implant filled to 420. Discuss this with your doctor before surgery and good luck.

You are worrying about small differences is size and I would recommend not stressing over this.  The volume differences that you describe really won't matter since they are relatively small differences.I would be more concerned about the type of implant.  Traditional saline implants have a more artificial feel, higher capsular contracture rate, and show rippling more than the newer Gummy Bear or Ideal Implants.  I would recommend seeing a Board Certified Plastic  Surgeon who routinely performs Gummy Bear and Ideal Implants before finalizing your surgery.

Congratulations on your breast augmentation. There is very little difference between the 420 cc and 430 cc breast implants. With such a small difference I would go with the larger. 

I wish we could be more helpful, but as every consultant will tell you, specific implant choices cannot be made without an exam and looking at photos of goal looks. You should not be concerned with specific implants, that is what you pay an expert for. You should show the surgeon photos of pre and post op patients that have the look you want. The surgeon then takes a number of implants to the OR (no one can be sure what an implant IN you will look like until it is IN you) and uses intrapoperative sizing to find the specific volume that creates your goal look.