Step-by-Step Guide to Using the Willow Pump Sizing Kit for a Perfect Fit

Getting the right flange size is one of the most important steps for comfortable and effective pumping with a wearable breast pump. If your flange is too small or too large, you may experience discomfort, reduced milk output, or skin irritation. The Willow Pump Sizing Kit takes the guesswork out of this process, helping you measure and select the correct insert for your Willow Go or Willow 360 pump.

In this guide, we’ll walk you through each step of using the Willow Pump Sizing Kit, from preparing to measure to testing the fit. We’ll also cover common fit issues and how to troubleshoot them, so you can pump with confidence and comfort.

Why the Right Flange Size Matters

The flange is the part of the pump that fits over your breast. When it fits correctly, your nipple is centered and moves freely without rubbing against the sides. This allows for efficient milk expression and prevents the tissue from being pulled too far into the tunnel, which can cause pain and reduce output.

A flange that is too small can cause friction, chafing, and even blocked ducts. A flange that is too large may pull in too much areola, leading to inefficient pumping and discomfort. The Willow Pump Sizing Kit helps you find the size that fits your unique anatomy, so you can pump comfortably and effectively.

• Proper fit reduces nipple pain and tissue damage.
• Correct sizing helps maximize milk output.
• Using the sizing kit prevents trial-and-error with multiple flange sizes.

What’s Inside the Willow Pump Sizing Kit

The Willow Pump Sizing Kit includes a set of measuring tools and sizing inserts that let you determine your flange size at home. The kit is designed for use with Willow Go and Willow 360 pumps, and it includes clear instructions for measuring your nipple diameter.

You’ll also find a sizing card or guide that helps you match your measurement to the correct insert size. Once you know your size, you can order the corresponding Willow Sizing Insert Set (2-pack) or Willow Go Flange Set (2-pack) to replace your current flange.

• The kit typically includes a measuring guide and sample inserts.
• It works with both Willow Go and Willow 360 models.
• You can reuse the kit if your size changes over time.

Step-by-Step: How to Measure Your Flange Size

Start by measuring your nipple diameter. Do this when your breasts are at their fullest, ideally before a pumping session. Use a soft measuring tape or the measuring card provided in the kit. Measure across the widest part of your nipple, not the areola. Write down the measurement in millimeters.

Next, consult the sizing card to see which flange size corresponds to your measurement. Willow flanges typically come in sizes like 17mm, 19mm, 21mm, and 24mm. If you’re between sizes, choose the larger size for comfort, as a slightly larger flange is easier to adjust than one that’s too small.

Finally, test the fit by using the sizing insert with your pump. Place the insert into the flange and do a short pumping session. Your nipple should move freely without touching the sides, and you should feel no pain or pinching.

• Measure when your breasts are full for the most accurate reading.
• Use the measuring card included in the kit for precision.
• If between sizes, round up to the next size.

Troubleshooting Common Fit Issues

If you experience nipple pain, friction, or low milk output after using your pump, your flange size may be incorrect. Common signs of a too-small flange include nipple blanching, redness, or difficulty inserting the nipple. A too-large flange may pull in too much areola, causing discomfort and inefficient pumping.

If you’re unsure whether the size is right, try the next size up or down and compare. You can also use the Willow Pump Sizing Kit again to re-measure, especially if your breast size changes due to engorgement or weight fluctuations.

For persistent issues, check that the flange is properly aligned with your nipple and that the pump is placed correctly. Sometimes a simple adjustment in positioning can resolve discomfort without changing the flange size.

• Nipple pain or pinching often indicates a too-small flange.
• Excessive areola pulled in suggests a too-large flange.
• Re-measure after major weight changes or pregnancy.

Tips for Comfortable Pumping with Willow

Once you’ve found your correct flange size, you can maximize comfort with a few extra steps. Use a nipple balm or lanolin before pumping to reduce friction. Ensure the pump is positioned correctly on your breast, and adjust the suction level to a comfortable setting—higher suction doesn’t always mean better output.

If you’re using a Willow Go or Willow 360, consider pairing your flange with a LaVie Warming Lactation Massager (2-pack) to help with let-down and milk flow. The gentle heat and vibration can also make pumping more comfortable, especially if you’re prone to engorgement.

Finally, keep your flanges clean and dry between uses. Replace them if you notice cracks or wear, as damaged flanges can cause irritation and reduce pump efficiency.

• Apply a small amount of nipple balm before pumping.
• Use a lactation massager to encourage let-down.
• Inspect flanges regularly for wear and replace as needed.

When to Re-Measure Your Flange Size

Your flange size can change over time due to hormonal fluctuations, weight changes, or weaning. It’s a good idea to re-measure every few months or whenever you notice a change in comfort or output. The Willow Pump Sizing Kit is a one-time purchase that you can use repeatedly.

If you’re about to return to work or start a new pumping routine, re-measuring ensures your pump is still working well for you. A proper fit is key to maintaining your milk supply and avoiding unnecessary discomfort.

• Re-measure after significant weight changes.
• Re-measure if you experience new pain or reduced output.
• Keep the sizing kit handy for future use.

Finding your correct flange size with the Willow Pump Sizing Kit is a simple process that can dramatically improve your pumping experience. By measuring accurately, testing the fit, and troubleshooting common issues, you can pump comfortably and effectively with your Willow Go or Willow 360. Remember to re-measure periodically and keep your equipment in good condition for the best results.