Momcozy Breast Pump Flange Size Guide

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Bra Size Nipple Measuring Guides

What is a Breast Pump Flange?

The flange is the breast pump part that comes in contact with your body when placed onto the breast and nipple, forming a vacuum seal with the areola. It's shaped like a funnel. The flange draws your nipple into the tunnel of the pump where milk is extracted.

Flanges are typically made of plastic or silicone and come in various sizes to accommodate different nipple dimensions.

Some breast pumps come with multiple flange sizes or offer smaller inserts or cushions to customize the fit within the flange. This reduces the opening of the tunnel where the nipple enters and allows for a more comfortable and effective pumping experience.

Why Breast Pump Flange Size Matters?

Whether the shield or flange size of your breast pump is right or not greatly affects your breast comfort and milk output. A properly fitted flange maximizes milk output, prevents nipple damage, and ensures effective milk pumping. If you want to ensure the most amount of milk during your pumping and comfort during and after pumping, getting the right measuring size of your nipples is very crucial.

Flange sizes typically range from 13 to 36mm, depending on brand. This measurement refers to the beginning of the flange tunnel, not the flange opening. Momcozy breast pumps include a standard 24mm flange and offer additional 27mm flanges for moms with larger nipples. We also provide inserts ranging from 15mm to 21mm to accommodate a variety of nipple sizes.

What Should Your Nipple Look Like in the Flange?

Your nipple should comfortably fit within the flange tunnel without rubbing or pinching. It should snug nicely inside the tunnel of flange. The areola should not be sucked into the tunnel.

If the flange is too small, your nipple might rub against the sides of the flange causing discomfort. If the flange is too large, the areola may be sucked in, which can reduce milk output and cause pain.

Too Small

Nipple rubbing against the flange

Correct Fit

Nipple snug nicely inside the tunnel of flange

Too Large

Nipple along with aerola is being sucked into the flange

How to Measure the Flange Size? Two Methods Introduced

To determine the best flange size for you, you’ll need to measure your nipple first.

Method 1: Use the nipple ruler or the normal ruler to measure.

Step 1: Stimulate your nipple to make it perk up.

Step 2: Hold the ruler at a perpendicular angle and line the 0 scale with your nipple base at the same horizontal line, also with the ruler edge meet your areola.

Step 3: Get the millimeters number between the nipple base and the nipple top, and the size measuring is done.

Method 2: Use the nipple ruler with holes to measure

Step 1: Stimulate your nipple to make it perk up.

Step 2: Place your nipple into the holes one by one to find out which one you can comfortably fit your nipples into, in a way that your nipple can be out through the hole totally, also the ruler can touch the areola at the same time.

Step 3: Get the size of the holes, then the size measuring is done.

How to Determine Your Momcozy Wearable Breast Pump Flange Size?

Momcozy includes a handy nipple ruler with holes in the breast pump set to make measuring a breeze. Please note that your left and right nipples may have different sizes, so please measure them both to get the exact size of them.

We recommend adding 1-3mm to your nipple measurement to determine your ideal flange size. Because nipple size can fluctuate when pumping, choosing a flange 1-3mm larger often provides a more comfortable fit. For personalized guidance, refer to our flange size chart below.  

Momcozy Breast Pump Flange Size Chart

Nipple Measurement Recommended Size What I Should Purchase
11-13mm 15mm 15mm Insert
13-15mm 17mm 17mm Insert
15-17mm 19mm 19mm Insert
17-20mm 21mm 21mm Insert
21-23mm 24mm Included, no purchase required
24-26mm 27mm 27mm Flange
27-29mm 30mm not included in the sale
Please stimulate your nipple to make it perk up before measuring the size

Remember, every mom is unique. While the 1-3mm works for many, it's essential to pay attention to how your body reacts during pumping. It is okay if your nipple touches the side of the flange tunnel, but excessive rubbing or discomfort isn’t. If you experience any issues, don't hesitate to try a different size.

Signs of a Correct Flange Size

Nipple movement: Your nipple should move in and out freely within the flange tunnel without pain or air gaps.  

Areola involvement: Only a small portion of your areola should be drawn into the flange.  

Comfort: You should not experience any discomfort or pain during pumping.  

Nipple condition: Your nipples should appear healthy without redness, blisters, or cracks after pumping.

Will My Flange Size Change?

Possibly! Your breasts may change between the third trimester and after giving birth. Also, your breasts may change through your breast pumping journey, so it's important to regularly check your flange size.

If you measure your nipples before beginning to pump or before you have your baby, you will want to add 1-3 mm to the measurement you found for your nipple diameter for choosing the correct flange size. This will allow for the amount of swelling that occurs during pumping.

Need more help? Please feel free to Email Us.

FAQs about Breast Pump Flange Size Guide

What is the most average flange size?
Will correct flange size increase milk supply?
Can you put too much areola in a flange?
What if you're in between flange sizes?

Download the measurement tool here

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