What is a Flange?
A flange is the funnel-shaped part of a breast pump that fits over your nipple and areola to create suction and extract milk. It helps form a seal around your breast, making pumping more efficient and comfortable. Flanges are usually made from hard plastic or soft silicone, and some brands offer flexible or cushioned options for extra comfort. You might also hear them called breast shields.
Most breast pumps come with a standard 24mm flange, but the majority of women actually need a smaller size—typically between 17mm and 21mm. If your flanges are too big or too small, you might experience pain, clogged ducts, or reduced milk output. Many moms don’t realize they’re using the wrong size because discomfort is often mistaken as “just part of pumping.”
That’s why measuring your nipple size is so important. A well-fitting flange can make pumping more comfortable, prevent soreness, and help you express more milk. If pumping feels painful or ineffective, your flange size could be the issue. Taking a few minutes to measure can make a huge difference in your pumping experience
Signs of an Incorrect Flange Size
Using the wrong flange size can cause discomfort and reduce your milk supply. Here are some common indicators that your flange might be too small or too large:
Too Small
- Excess areola gets pulled into the flange tunnel instead of just the nipple.
- Your nipple stretches too far into the tunnel and swells significantly.
- Pumping feels uncomfortable or painful.
- You experience clogged ducts or incomplete milk removal.
Too Large
- Your nipple rubs against the flange tunnel, causing friction and pain.
- Your nipple turns red, sore, or cracked after pumping.
- You feel pinching or pain while pumping.
- Milk output seems lower than expected.
If you notice any of these signs, adjusting your flange size may significantly improve your pumping experience.
How to Measure for Flanges
Step 1: Gather Your Measuring Tool
- Option 1: Buy a cheap circular ruler on Amazon – 📏 Buy circular ruler here
- Option 2: Use our free printable nipple ruler – 📄 Download circular ruler
Step 2: Prepare for Measuring
- Make sure you haven’t pumped recently. Your nipple should be in its natural, relaxed state for the most accurate measurement.
- If you’re having trouble measuring because your nipple is too soft or difficult to see, gently stimulate it by rolling it between your fingers or applying a cold compress to help it become erect.
Step 3: Measure Your Nipple Size
- Gently place your nipple into the holes, starting from the largest and moving smaller until you find the smallest hole your nipple fits through comfortably. If you try a smaller hole and don’t fit, the previous size is your measurement.
Step 4: Add the Right Amount
- For standard pumps, add 1mm to your measurement.
- For wearable pumps, add 2mm to allow a bit more movement.
Why Flange Size Matters
When it comes to pumping, the right flange size can make or break your experience. A properly fitting flange provides:
- Comfort: Reduces pain and prevents nipple trauma.
- Efficient Milk Extraction: Ensures maximum milk output and prevents clogged ducts.
- Breast Health: Helps prevent mastitis, soreness, and swelling.
Incorrectly sized flange can cause:
- Pain and discomfort due to excessive rubbing or stretching.
- Nipple trauma, including redness, cracking, or soreness.
- Low milk output from improper suction and milk removal.
- Clogged ducts and mastitis, leading to painful inflammation.
A well-fitting flange allows your nipple to move freely within the tunnel without excessive friction while ensuring that milk is effectively expressed. Finding the perfect size might take some trial and error, but it’s worth the effort for a pain-free and productive pumping journey.
Flange types and Inserts
The main difference between Spectra-style and Medela-style flanges lies in their design and compatibility with different breast pumps:
- Spectra-Style Flanges:
- Have a wide-neck design.
- Compatible with Spectra bottles and some other wide-neck bottles.
- Typically come with duckbill valves, which create strong suction and are easier to clean.
- Medela-Style Flanges:
- Have a narrow-neck design.
- Compatible with Medela bottles and other narrow-neck bottles.
- Use membrane-style valves, which can require more maintenance but are widely available.
Adapters are available if you want to mix and match different brands of pumps, flanges, and bottles.
Silicone inserts are available to modify the fit of larger flanges. These inserts help those with smaller nipples achieve a better seal, improving comfort and suction efficiency. Using inserts can also reduce irritation and enhance the pumping experience for individuals who struggle with standard flange sizes.
Spectra Style Flange
Medela Style Flange
Flange insert