Basics on Flange Sizing:
Sizing Guidelines, Factors, Cushions and Inserts

Flange sizing is a hot topic in the lactation world and in many peer-to-peer groups. Let’s dive in to flange sizing and some of the key aspects that need to be considered when trying to properly fit flanges. I will also talk about the importance of having a properly fitted flange.

○ Why is flange fit so important?
First and foremost, a properly fitted flange can be the difference between a painful, low output pumping journey vs. an enjoyable and productive one. What I mean by this is that using the wrong size flange, whether too small or too large can cause irreversible tissue damage, low milk output, discomfort, and over time may affect your overall milk production. It is often common for parents who are experiencing these things to become discouraged, have perceived perceptions of their milk production as being inadequate, or even discontinue their journey cutting it shorter than expected or desired.

○ What tools may be used as a baseline for sizing nipples to flanges?
There are a few tools on the market available for parents to purchase to size themselves. This ranges from silicone rules, plastic millimeter rulers, paper print offs, paper rulers, and coin “tricks.” While this is a wonderful option, I always suggest getting sized by a lactation professional who is trained and experienced in flanges and breast pumps. A simple measurement does not take in to account for all the factors that need to be considered when determining a proper fit. I offer virtual flange sizing CLICK HERE to submit a request through a secure Google Form.

○ What needs to be taken into consideration when determining a fit?
There are a few key factors along with nipple size, nipple shape, and nipple elasticity that will also influence a flange sizing.
1. Measurement of the nipple diameter BEFORE pumping.
2. The functionality (the visual mobility, expansion and elasticity) of the nipple in the flange tunnel WHILE pumping.
3. How far postpartum the parent is. Pregnancy and immediate postpartum are not ideal times to size flanges, but, in some instances it is necessary. If sized immediately postpartum, I advise having a follow-up sizing within 4-6 weeks after all swelling resides. Sizing may also change over the duration of your breastfeeding journey. Most* parents find that over time their size may increase slightly in response to frequent nipple stimulation and that feeds/pumps naturally draw nipples out.
4. The type of pump the parent is using. Is it a standard pump or a “hands free/ wearable” pump? What settings are they typically using while pumping and why? For example, the Willow pump has specific guidelines for flange sizing.
5. The type of flange style. Is it a one piece, a 2- piece connection, a cup, or a specialty flange?
6. The parents comfort level and output using the flange.

○ How do I know it’s a good fit?
Using a good fitting flange will have no areola being pulled into the tunnel, the nipple will be free to mobilize and expand in the tunnel, there is no rubbing or chaffing of the nipple on the tunnel wall, and the parent reports no discomfort and has efficient emptying of milk from the chest/breast. Sizing is not “one size fits all” and we are learning that parents regularly measure smaller than what comes standard with most breast pump brands!

○ What are special types of flanges?
There are many different flange styles and brands on the market today. Two common specialty flanges are the LacTeck and Pumpin’ Pal. Visit their website for more information about these specialty flanges and their specific sizing and uses.

○ When to consider the use of inserts or cushions?
When thinking of flange sizing for certain breast pump brands, there is not a whole lot of sizing variety on the market. Specifically for some of the newer “hands free” or “wearable pumps”. In the last few years, there has been a drastic improvement and push for smaller flange sizes to be offered from breast pump companies and “off market” suppliers. We are now seeing sizing for standard pumps ranging as low as 10mm and as great as 40mm. Some of the top “hands free” brands have also expanded their flange sizing to offer lower sizes (as low as 19mm) and have began offering inserts as a method of reducing flange sizes.

Now let’s talk about inserts! What are they? They are typically a durable, soft silicone material that is placed in the flange tunnel to reduce the diameter of the tunnel. When should they be used? Inserts should be considered only when the sizing for your flange is not available for you by your pump brand or an off market retailer. Inserts may also help with reducing elasticity in some cases. Here are some popular insert brands: Maymom, Willow, LOZAEVE, and Nenesupply.

What are cushions? Cushions are usually soft silicone, stretchy in material and used to maximize comfort, reduce elasticity, and help parents who are in between sizes. For example, a cushion may be used to reduce the flange tunnel diameter for parents who may be too small for a 24mm but too large for a 21mm. Beaugen Cushion is a popular brand that I have seen parents express great results from.

If you have any questions or concerns about your infant’s health or well-being, I advise you to contact your health care provider for evaluation and guidance. The information listed above is general advice and is not meant to replace the advice from your specific health care provider. If you are having concerns about breastfeeding, or struggling with latch or milk production, I suggest you reach out to a lactation professional who can work closely with you and your provider.