Natrelle style 20 HP 600cc silicone implants too large? Height 5"7 weight 150-160 lbs. Pre op 34B (Photo)

Hi. Thanks for your question. 600 cc high profile implants may look too large for you; 475 should give you good volume based in your pictures. Of course, a formal virtual or in-person consultation would be required to determine your ideal procedure. Augmentation patients do need to understand that larger implants have higher long term revision rates and will stretch the skin and flatten the breast tissue. Some problems may be irreversible. Patients need to seriously consider these risks, especially when they start with good breast esthetics.  I hope this information helps. Good luck. --Dr G. 

Might be OK But over internet very hard to be exacting. Obtain IN PERSON consultations with boarded PSs. 

No one can tell you what's the right implant size for you. As an experienced Plastic Surgeon, I counsel my patients on an appropriate size and shape range to give a natural looking and feeling result, given their chest wall dimensions and breast tissue compliance. After that,  patients " try on" appropriate implants to finally decide on their implant. If your surgeon feels that your breast will accommodate a large implant (600cc is a relatively large implant for augmentation) and if you want the kind of proportions that that implant will give you, go with your desires. Larger implants do have somewhat of a higher risk of complications, which can be due to exceeding the capacity of your own tissue to accommodate them. Make sure you and your surgeon agree on a your surgical plan, and your surgeon feels that it is an appropriate implant for you! 

To properly answer your question you need an in person consultation with measurements of your base breast with an sizing system evaluation.That said based on your photograph you appear to have full wide-based breast.  The high-profile implants have a narrower base and a wider base moderate profile plus might be an appropriate implant for you.Be aware that 600 cc breast implants are quite large.  In general potential complications are higher with implants over 500 cc based on a recent study.  Your original thought of a 475 cc breast implant might be a better option.