Flange sizing questions answered + my favorite flange sizing video

Read Time | 6 minutes

60% of pumping parents are using the wrong size flange.

Actually, I just made that percentage up, but it seems like more than half of the pumping parents I see in my practice are using an incorrect size.

A stat that I know for certain: Using a properly sized flange may increase your pump output by 20%.

Proper sizing is key to both pumping comfort and long-term milk-removing success.

So I'm here to answer the most common questions regarding flange sizing!

How do I know my flange size?

Your flange size is determined based on the measurement of your nipple base. To know your flange size, you measure from one side of your nipple to the other and then add 1-3 mm depending on when you measure it (before or after pumping).

Many people struggle with knowing what part to measure- you measure the 'nipple button,' which is the part that sticks out when you're cold (or horny). Where the nipple attaches to the areola-the pigmented area surrounding your nipple- tends to be the widest part, which is where you want to take the measurement.

Nipples come in a variety of shapes and sizes, and for some, the widest part of the nipple is NOT the nipple base. In this case, measure the diameter (from one side to the other) of the widest part, and you should get an accurate measurement for what flange size you need.

Please note: Nipple size changes after delivery and during lactation. Most people increase in nipple diameter the days following birth, so if you measure prenatally, keep that in mind.

What happens if flanges are too big?

If your flanges are too big, pumping will likely be uncomfortable. In the event it's not causing any pain, problems still could arise down the line if breast drainage is not optimal, leading to delayed onset low milk supply.

An easy way to tell if your flange is too big is that your areola will be pulled into the breast flange tunnel. Some parents find that they need to size up for comfortability reasons- if this is the case for you, ensure you're utilizing strategies to thoroughly empty the breast and optimize milk output each expression session.

What is the smallest flange size?

The smallest flange size is sold by Maymom and measures in at 13mm. Maymom makes aftermarket flanges for big pump brands like Spectra and Medela, which can be purchased for less than $30 bucks. The next size up is 15mm, and they make a 17mm- all of which are under the standard 24s that come with most pumps.

Full disclosure: I have tiny nipples. I've personally used the 15mm Maymom flanges for the Spectra and would definitely recommend for my small nip-having folks.

How should flanges fit?

Flanges should be comfortable and be large enough for your nipple button to fit in the tunnel but not so big that your areola tissue gets pulled into the tunnel. Nipple elasticity varies among people so some people will always have areola tissue in the tunnel despite proper sizing.

THE most important thing is the comfortability. Pumps don't suck out milk; they stimulate a letdown (milk ejection reflex).

Do you know what the most significant thing that prevents a letdown? Pain.

What size flange do I need?

The size flange you need will depend on your nipple size, the pliability of your nipple, the elasticity of your areola tissue, and the shape of your breasts. Pump companies say the average consumer will need roughly either 24mm or 27 mm flanges.

It's been my experience that there is a large part of the pumping population that needs smaller and larger sizes. It's frustrating to get a pump and find out after you've bought it that there are no flanges in the size you need.

A limited offering of a wide range of sizes by manufacturers means that some people are left to settle with the wrong size flange. If this is you, pick whichever is the most comfortable. And make sure you're using hands-on pumping.

How do I know if my breast pump flanges are the right size?

If pumping hurts -either during or after pumping -regardless of the suction level you pump on, the odds are high that you're using a flange that's too big or too small. A well-fitted flange will be comfortable, stimulate the letdown well, and result in decent output assuming there are no issues with milk production.

I've covered all the signs of a properly fitted flange in my FREE Ultimate Flange Sizing Guide. It includes some of the information in this post- and more. If you're still confused about flange sizing, it's worth taking a look.

My favorite flange sizing video

Full disclosure, I am not partial to Medela. I can't think of the last time, outside of the Symphony, that I've recommended Medela breast pumps.

There are a few reasons why, but that's a post for a different day.

With that said, the best video I've seen to show how the nipple is supposed to respond when using an appropriately sized flange is this one. Just know it should look the same irrespective of the flange brand or the pump model you use.

The most important part (in my option) starts around the one minute mark.

If you still have discomfort or low pump output after reviewing the video, checking out my flange guide, and making any necessary adjustments, it's time for a professional flange fitting! I offer same-day video consults. :) If you have questions about the process, shoot me a message!


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