Flange Size Matters: How to Measure and Fix Pump Pain
If you’re pumping and experiencing pain, rubbing, or low output—it might not be your pump. It might be your flange size.
Proper flange sizing is one of the most overlooked parts of successful pumping. A well-fitting flange can improve comfort, output, and milk flow. Let’s break down how to measure, fit, and fix your setup for better results.
What Is a Flange?
The flange (or breast shield) is the funnel-shaped part that fits over your nipple and areola. When you pump, suction draws the nipple into the tunnel to extract milk.
If the flange is too big or too small, you’ll likely see:
Pain or friction
Nipple blanching or swelling
Cracked skin
Poor output or clogged ducts
How to Measure Correctly
Measure your nipple (not areola) after a feeding or pumping session.
Use a ruler or measuring tool in millimeters across the base of the nipple.
Add 1–3 mm to that number to find your ideal flange size.
Example: If your nipple measures 18 mm, try a 21 mm flange.
Many people use the wrong size because most pumps come with 24–27 mm flanges by default. (CDC, 2023)
Signs Your Flange Fits Well
✅ Nipple moves freely in tunnel without rubbing
✅ Areola movement is gentle, not pulled deeply
✅ No pain or blanching
✅ Milk flows within 1–2 minutes of pumping
✅ Nipple returns to normal color/shape afterward
Adjusting Pump Settings
Start on low suction and gradually increase to comfort.
Avoid turning suction to max; stronger isn’t better.
Use the “letdown” mode for the first 1–2 minutes.
If you’re using wearable or portable pumps, remember: fit can differ slightly from traditional pumps.
When to Replace Pump Parts
Replace parts regularly for optimal suction:
Duckbills/membranes: every 4–6 weeks
Tubing: every 3 months
Flanges: every 6 months or sooner if warped
Output Troubleshooting
Low output doesn’t always mean low supply. Try:
Checking flange size
Relaxation techniques (deep breathing, baby photos)
Warm compresses before pumping
Power pumping once daily for 3–4 days to boost supply
The right flange size changes everything—comfort, confidence, and consistency. Still unsure about your fit or output? Book your virtual lactation consult now and get professional help finding your perfect flange size and pumping setup.
The information provided in this blog is for educational and informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Reading this content does not establish a patient–provider or professional relationship between you and Thrive Lactation Center or Sarah Schooler, RN, BSN, IBCLC.
Always seek the advice of your physician, pediatrician, or qualified healthcare provider regarding any questions you may have about a medical condition, breastfeeding, or your health. Never disregard or delay seeking professional advice because of something you have read here.