5'3", 125 lbs, petite frame. Sientra sizing question - 290cc or 330cc? Or won't it matter much?

Hi Jordanna.Some people might not think 40 ccs would make a big difference, but this is a very personal decision for you, so every little cc matters. As someone else pointed out, you've got a petite frame, so the difference between the two sizes might be visible, at least to your eyes. I think that since you're going with the oval shape and moderate profile, that will go a long way towards the natural results you want. In general, among patients who are struggling between 2 sizes, I find that more women wish they had gone slightly bigger than smaller. Discuss your concerns with your surgeon if you're still not sure, and maybe he or she can help you visualize the differences with digital imaging. I commend you for being so thorough and doing your homework. Best of luck with your surgery.

The 40cc difference will likely not be a visible difference. I think either size implant will give you more than 1 cup increase.

Subtleties make all the difference from a good result to a great one.  In your case that may be close to a 1/2 cup size difference. 3 D computer imaging may help you.  I use Crisalix in my office and it has helped many patients.  It's a matter of taste and can be hard to predict what you will like when you don't have much breast tissue.