Between the tubes and wires, mechanics and logistics, the whole pumping process can feel, well, like a process. But one thing can make it considerably easier: double-checking that you're using the right breast pump flange size.
It can make the difference between a frustrating struggle to express enough milk and a situation where you can more easily (and painlessly) produce plenty for your baby. Here's what you need to know about flange sizes to make the most of your pumping sessions.
What is a breast pump flange?
A breast pump flange is a funnel-shaped piece of plastic that fits over your nipple. It forms a vacuum seal around your areola, and then draws your nipple into its funnel to extract milk.
Most pumps come with a standard 24 millimeter (mm) flange. But they’re available in a wide range of sizes, generally anywhere from 21 to 36 mm. The size indicates the diameter of the small tube on the flange's narrow edge.
You can find different-sized flanges through your pump manufacturer, sites like Amazon or any baby supply store.
Why is flange size important?
The right flange fit will help you express as much breast milk as efficiently as possible. Your flange size generally depends on your breast tissue and skin elasticity. If your flange is too tight, it will constrict your breasts, which can cause clogged milk ducts that don’t release milk as quickly.
But if your flange is too loose, you won’t remove all the milk from your breast, which can lower your milk production. It can also cause unnecessary nipple pain and even injury to your nipple. If pumping hurts, it can impede your milk supply. You’re also less likely to stick with it.
Which flange size should you use? Check this flange size chart
To find your size, check the website of your pump's manufacturer. Most companies offer a size guide for flanges based on your nipple size. Here's an approximate guide you can use as a flange size chart:
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- Up to 17 mm: 20 to 21 mm flange size
- 17 to 21 mm: 24 mm flange size
- 21 to 25 mm: 27 to 28 mm flange size
- 25 to 29 mm: 30 to 32 mm flange size
- 29 to 32 mm: 36 mm flange size
To measure your nipple diameter (its width), you'll need a ruler or a measuring tape. You can also estimate with coins: A dime is approximately 18 mm, a penny is 19 mm, a nickel is 21 mm and a quarter is 24 mm.
Before you measure, stimulate your nipple, either by rolling it between your thumb and finger or applying ice to it, to make sure you have its full size. Focus on its diameter at the base, and don’t include the areola. Remember to measure both of your nipples as they can be different sizes.
Flanges vary from company to company, so you may want to try a few out. You might find that another brand’s flanges work better with your body. It can take some time to find the ideal gear, but most pump and flange combos are totally fine.
Remember also that your nipple size (and hence your flange size) may fluctuate throughout your breastfeeding journey.
How to tell if you’re using the correct flange size
Most lactation consultants recommend using the "COMFY" test to help determine the right flange size. Here are the five major guidelines that the acronym stands for:
- Center nipples move freely. Your nipple should move freely in and out without touching the sides of the tunnel and without redness or pain.
- Only a little areola tissue should be pulled into the tunnel. You should see a bit of areola pulling into the tunnel with each pump cycle, but not too much or none at all.
- Motion of your breast is gentle and rhythmic. Your breasts should move back and forth every time the pump moves, but gently.
- Feels comfortable breast pumping. Your breast pump shouldn't cause any pain and tenderness.
- Yields well-drained breasts. Your pump needs to remove the majority of your milk from your breasts to keep up your milk production. Your breasts should feel noticeably softer and lighter once you’re done with your session.
How to tell if your flange is too big or small
Some signs that your flanges don't fit quite right include:
- Your breasts are moving too much or too little while pumping. Movement should be gentle, much like the movement of your nipple within the tunnel.
- Your nipple is rubbing the sides of the tunnel, causing discomfort.
- Your nipple and part of your areola are being pulled into the tunnel.
- Your nipples are red or white after pumping. This can indicate too small a flange.
- Your breasts still feel full after pumping. If they’re heavy and harder, that means all the milk hasn’t drained and your flange is possibly too big.
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