Everything You Need to Know About Flange Sizing Kits

1. What Is a Flange Sizing Kit?

A flange sizing kit helps you determine the correct flange (breast shield) size for your breast pump. Instead of guessing or relying on general charts, a sizing kit includes multiple measuring tools or inserts designed to help you:

• Measure nipple diameter accurately
• Try different flange sizes for comfort
• Improve milk flow
• Reduce pain or irritation
• Support more efficient pumping sessions

Most kits include sizing rings and inserts that match common flange sizes such as 15mm, 17mm, 19mm, 21mm, 24mm, 27mm, and 28–30mm. MomMed’s Flange Sizing Kit provides soft inserts and clear measuring tools to help moms find their best fit quickly and comfortably.

2. Why Flange Size Matters

The right flange size directly impacts pumping comfort and milk production. Using the wrong size can lead to several issues:

Discomfort and Pain

• Nipple rubbing inside the tunnel
• Cracked or stretched nipples
• Redness around the areola

Low Milk Output

A flange that’s too big or too small prevents proper suction, resulting in slow flow and inefficient emptying.

Blocked Ducts or Engorgement

Poor emptying increases the risk of clogged ducts or mastitis.

Nipple Damage

Incorrect sizing can pull in too much areola or compress the nipple excessively.

Choosing the right flange ensures strong suction, efficient milk removal, better comfort, and improved pumping outcomes.

3. How to Measure Your Nipple Correctly (Step-by-Step)

The most important part of flange sizing is measuring nipple diameter—not the areola. You can measure using a ruler, sizing card, or the tools included in a flange sizing kit.

Step 1: Measure After a Warm Shower or Pumping

Your nipple should be in its natural state—avoid measuring when cold or swollen.

Step 2: Measure Only the Nipple

Place the sizing ring or card around the nipple:

• Do not include the areola
• Measure across the widest point of the nipple base
• The nipple should fit easily without squeezing

Step 3: Add 1–3mm to Your Measurement

This extra room ensures comfort during suction. For example, if your nipple measures 17mm, your flange size may be 19mm or 20mm.

Step 4: Test Different Sizes

Use sample inserts to find the one that offers the best comfort and output.

Step 5: Remeasure Regularly

Nipple size can change due to hormones, pumping frequency, or engorgement, so reassessing monthly is ideal.

4. Signs You Are Using the Wrong Flange Size

Flange Too Small

• Nipple rubs the tunnel walls
• Pinching or pain
• Slow or minimal milk output
• Redness at the nipple base

Flange Too Large

• Too much areola is drawn into the tunnel
• Nipple expands excessively
• Areola swelling (edema)
• Reduced output

Ideal Fit

• Nipple moves freely in the tunnel
• Minimal areola pulled in
• Comfortable suction
• Efficient milk flow

5. How to Use a Flange Sizing Kit (Practical Instructions)

1. Start by measuring your nipple with the tool provided.
2. Choose 2–3 flange sizes that match your measurement.
3. Insert each flange or insert into your pump.
4. Test each during a full session and observe comfort and output.
5. Compare results and choose the size that works best.
6. Reassess sizing every few weeks.

6. Advantages of the MomMed Flange Sizing Kit

MomMed’s kit is designed to help moms find the perfect fit for wearable breast pumps like the MomMed S21, MomMed S10 Pro, and MomMed S33 Luma.

• Multiple sizes for accurate fitting
• Soft, flexible inserts for comfort
• Compatible with all MomMed pumps
• Easy to clean and long-lasting
• Helps increase milk output
• Reduces nipple irritation and pain

Whether you’re new to pumping or experienced, the right flange size improves comfort, efficiency, and breast health.

7. Common Questions About Flange Sizing

1. How do I know if I need a smaller or larger flange?

If your nipple rubs → go bigger. If too much areola is pulled in → go smaller.

2. Does nipple size change?

Yes, many moms experience changes throughout their breastfeeding journey.

3. Should I measure both breasts?

Yes, each nipple may require a different size.

4. Can the wrong size reduce milk supply?

Yes. Poor suction leads to less milk removal, which lowers supply over time.

5. How often should I remeasure?

Every 3–4 weeks or anytime you experience discomfort.

6. Do inserts work the same as full flanges?

Yes. Inserts reduce tunnel size and can improve comfort and fit.

Conclusion

A flange sizing kit is an essential tool for breastfeeding and pumping moms. By accurately measuring nipple size and testing different flanges, you can pump more comfortably, protect your nipples, and maintain a healthy milk supply. MomMed’s Flange Sizing Kit makes the process simple, reliable, and mom-friendly, supporting a smoother and more efficient pumping journey.