Your Guide to Proper Flange Sizing

Mommy Care Team
Your Guide to Proper Flange Sizing

Everything You Need to Know to Get the Best Fit with Your Breast Pump Flanges

Each breast pump is a bit different, comes with a set of flange or shields in various sizes, and it’s own settings and adjustments. One of the keys to successful pumping regardless of what pump you choose, is achieving a proper fit with your breast pump flanges. In this post you’ll find all of the information that you need to be able to properly determine your breast pump flange size.

Pump Flanges

Sometimes also called breast pump shields, your flanges are the part of the pump that come into contact with your nipple, areola, and surrounding breast tissue. The flanges should form a seal with your nipple and areola so that the breast pump can create suction. Each pump will come with a set of flanges. Most brands include two different flange sizes. These are often their most commonly used sizes, but they are not the only sizes available.

Why is the Right Fit So Important?

Flange fit not only makes pumping possible, using a flange that is too big or too small can have a potentially negative impact on your pumping experience. When a flange is too big, you can have too much of the areolar tissue pulled into the tunnel. You can tell when this happens as the tissue can change color a bit and become almost a white color. This compresses your milk ducts and impedes the milk flow. In short, using a flange that is too big can reduce the amount of milk you are able to pump. 

When your flanges are too small you can experience friction from your skin rubbing against the flange tunnel. This causes soreness and tender skin. Similarly to flanges that are too large, this restricts milk flow and can lead to clogged ducts. Your nipple tissue can become pinched or squeezed which can nipple trauma. 

Let’s Talk About Nipples

This post might be about breast pump flanges, but really it comes down to nipples. Your nipples fit into the breast pump flange or shield. And the suction of the pump works to mimic the suckling of a baby and inspire your let down reflex. For more on let downs, check out this post.

What is the difference between the nipple and areola?

Unless you work with us, there’s a likely chance that you don’t talk about the anatomy of a breast everyday. Let’s take a minute to reacquaint ourselves with our breasts in terms of a breast pump.

Simple diagram of a breast showing nipple and areola

When measuring our breast for the proper fit with our pumps, there are three main parts with which we need to be familiar: Nipple, Nipple Base, and Areola. At a quick glance, the nipple and areola are the darker colored parts of your breast. Your nipple is the part that extends from the main part of your breast and your areola is the darker circle where the nipple meets your breast. Where these two join is the base of the nipple.

What part you need to measure for your pump.

Now that we have identified the parts of our breast involved in pumping, we can begin to measure them for a proper fit. Looking down at your breast, you want to measure the diameter of your nipple from one side to the other. This is taken at the nipple base. Our diagram is shown from the side, but it's easier to do if you look straight down at your breast.  You’ll use a ruler and measure from one side of your nipple to the other.

Download this safe and simple nipple measuring roller tool from BeauGen!

Nipples Can Come in Different Shapes and Sizes

When measuring to find your proper flange size, it is important to measure both nipples. Or bodies are not mirror images. Our breasts, and even our nipples can be different sizes. We have more on the differences here in this post.

Nipples Can Change Over Time

Measuring your nipples for pumping is not a one time occurrence. Over the course of our breastfeeding journeys, our bodies, and nipples can change. Sometimes you might be able to notice a change in the way your flanges are fitting and other times, you might notice a change in your output. Other times, you might notice the change. It’s a good idea to measure your nipples from time to time over as you pump.

If you have already started your pumping journey, and you are experiencing irritation or pain while pumping, your nipples could be a bit swollen. Adjusting your flange size, using a bit of lubrication, and potentially a pump accessory like breast pump cushion might alleviate this swelling and change the size of flange that you need.

Finding Your Flange Size

Download our free sizing tool. Other printable sizing tools require you to cut out a ruler. BeauGen’s mission is safe and healthy breasts as well as successful pumping. We don’t want you to be putting sharp cut printer paper near your sensitive breast tissue. We’ve designed a simple sizing guide that allows you to simply roll a piece of paper and easily measure the base of your nipple.

Take BeauGen's ruler and place it under your nipple. Roll the paper until the ruler lines up directly with both sides of the base of your nipple.

How to Achieve Your Proper Sizing with Pumping Accessories

Pump brands will offer different sized flanges. Sometimes you can find the right fit with a different sized flange, but some moms may fall in between sizes. In this case, you might be able to find an additional sizing aid from your pump brand, a stand alone company, or you can use our breast pump cushions!

Often sizing accessories are either plastic or silicone. Our breast pump cushions are made of a soft and stretchy plastic. They aren’t hard plastic with ridges or sharp angles. And they are not made of silicone. Moms with latex allergies can use the cushions without fear.

BeauGen Cushions for Accurate Sizing

By inserting cushions into your breast pump flanges or shields, you can reduce the overall size of your flange by two millimeters. So if you have 27 a millimeter flange and need a 25 millimeter flange, all you have to do is pop your BeauGen Breast Pump Cushion into your flange and you are set. 

Flange sizing with BeauGen Breast Pump Cushions

If you need to reduce your flange size even more, you can fold the cushion in half, like you’re folding down a turtleneck sweater. This will double up the cushion in the tunnel of your breast pump flange, making it four millimeters smaller. 

Wearable Pumps

Because these pumps are designed to be worn inside of your bra, they tend to be a bit smaller. This means that the tunnels of their flanges or shields are shorter. These flanges have a small hole inside the flanges to create the suction. If you insert the cushion directly into this flange, it will block these holes and reduce the suction. To use the BeauGen Cushions with these pumps you need to fold the tunnel of the cushion in half.

Wearable pumps and using BeauGen Cushions

Lubrication for Better Experience

Your breast pump flanges need to be a bit snug to work, but many moms can find that this causes painful friction. Using food safe lubrication like coconut oil is a great way to maintain proper flange fit while also reducing friction. These lubricants can also help to soothe and heal the sensitive skin on your nipple if and when it does become irritated. 

If you are using flange accessories that potentially create additional hard plastic angles or edges, using a lubricant can be even more effective in safeguarding your skin.

Reasons to Use Lubrication with BeauGen’s Cushions

Whether you choose to use our cushions to reduce friction or to get a better fit with your flanges, you can and should consider using lubrication. There are a few different reasons to use something like coconut oil or Nipple Crack with your cushions. The first reason is that using a lubricant can slightly prolong the life of your cushions. This can save you time and money. Longer cushions life means less times you have to break in new cushions.

The remaining reasons to use lubrication with your cushions help to improve the experience.  As the cushions come, they are a bit sticky or tacky. Some moms like this as it aids in inserting the cushions into your flanges. However for moms who need to eliminate friction, adding lubrication can make your skin stick to the cushions less. The lubrication also makes the cushions more translucent, which helps with nipple alignment. It also helps make training the cushions easy. Lastly, for the smaller sizes like 21mm the lubrication makes it easier to insert your cushion into the flange. 


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The new nipple measuring roller is awesome, it’s going to revolutionize nipple measuring for mamas everywhere!


The new nipple measuring roller is awesome, it’s going to revolutionize nipple measuring for mamas!


The nipple measuring roller is such a great idea! It’ll revolutionize nipple measuring for mamas everywhere!


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