Pump flange fit beyond the 2 mm rule
The standard “just add 2 mm” guideline (or using whatever size came in the box) does not work for every body. Fit affects comfort, output, and whether pumping feels sustainable.
Hypermobility, breast shape, and how your tissue responds to a particular pump all influence whether a flange size works.
Trying a size up and down from what you expect — and watching for rubbing, swelling, or poor output — is more useful than a single rule of thumb.
A back-to-work or pumping consult can cover flange fit, schedule, and keeping supply going when you return to work.