If you try the next size up and get more milk, does that mean it's the right size for you? Not necessarily! It could mean that the previous smaller size wasn't applied deeply enough and/or it wasn't the right size, either, or something else may be wrong.
There's a big risk to using a flange size that's too large. Over time (how much depends on many factors), using a flange that's too large can decrease your milk supply, lead to plugged ducts, and even cause mastitis because of swelling. Most nipples will swell to fill the larger available space in the tunnel and swelling compresses milk ducts in the nipple making it harder for the milk to flow and drain well.
Over the more than twenty years we've been in business, we've seen countless people size up to a larger flange and get more milk initially, which seems to confirm it's a better size. But a few weeks later, they get a plugged duct or mastitis because the compressed milk ducts from swelling kept the milk from draining thoroughly.
That's why it's so important to find your correct flange size and make sure it's being applied and used optimally. And that's why we have extensive Knowledge Base articles about fitting and using our flanges, and an expert support team to help if you need any guidance. We're here for you!
See also: Selecting the Right Flange Size to Use
Reviewed by Jenn Foster, MS, IBCLC, CD
February 8, 2022