Getting the right fit with your wearable breast pump is the single most important factor for comfort and milk output. If you’ve ever experienced nipple pain, chafing, or noticed that your output has dropped, the culprit is often an incorrect flange size. The Willow Sizing Insert Set is designed to solve this problem by allowing you to customize the flange opening to match your nipple measurements.

In this guide, we’ll walk you through how to use the Willow Sizing Insert Set, explain why a proper fit matters, and share troubleshooting tips to help you get the most out of every pumping session. Whether you’re a first-time user or a seasoned pumper, this step-by-step tutorial will ensure your Willow pump works as effectively as possible.

Why a Perfect Fit Matters for Your Willow Pump

A correct flange fit is not just about comfort—it directly impacts how much milk you can express. When the flange is too large, your areola gets pulled into the tunnel, which can cause swelling and reduce milk flow. Conversely, a flange that is too small can cause friction on the nipple, leading to pain and even micro-tears, which increases the risk of mastitis.

The Willow Sizing Insert Set helps you achieve the ideal fit by providing multiple insert sizes that snap into the flange. This customization ensures that your nipple is centered and free to move without rubbing against the sides. The result is a more efficient let-down, better drainage, and a more comfortable experience overall.

  • Prevents nipple trauma and soreness
  • Improves milk output and emptying
  • Reduces the risk of clogged ducts and mastitis

Step-by-Step: How to Use the Willow Sizing Insert Set

Start by measuring your nipple diameter. Use a ruler or a nipple sizing card (often included with the insert set) to measure the width of your nipple at the base, not the areola. For the most accurate reading, measure after a few minutes of pumping or a warm shower, as nipples can expand slightly.

Once you have your measurement, select the insert that matches your size. The Willow Sizing Insert Set typically includes sizes ranging from 15mm to 21mm. If you are between sizes, choose the smaller size for a snugger fit, as this often yields better results. After selecting, simply press the insert into the flange tunnel until it clicks securely into place.

Now you’re ready to pump. Place the flange over your breast, ensuring your nipple is centered. As you pump, check for any signs of discomfort or excessive pulling. Your nipple should move freely within the tunnel without touching the sides. If you feel any pinching, try a different insert size.

  • Measure your nipple at the base, not the areola
  • Choose the smaller size if between sizes
  • Ensure the insert is fully seated before pumping

Troubleshooting Common Fit Issues

Even with the correct insert, you might encounter issues. If you notice that your nipple rubs against the side of the tunnel, you may need a smaller insert. If you see areola being pulled in, try a larger insert. It’s also important to remember that your nipple size can change over time, especially in the early weeks postpartum, so re-measure periodically.

Another common concern is that the insert may become dislodged during pumping. To prevent this, always double-check that the insert is firmly snapped in before each session. If you find that the insert keeps popping out, consider replacing it with a new one, as wear and tear can affect the fit.

  • Re-measure your nipples every few weeks
  • Check insert security before each use
  • Replace inserts if they become worn

Maintaining Your Insert Set and Accessories

Proper care of your Willow Sizing Insert Set is essential for hygiene and longevity. After each use, wash the inserts with warm, soapy water and allow them to air dry. Avoid using harsh brushes that could scratch the surface. You can also sterilize them according to the manufacturer’s instructions.

In addition to the inserts, consider investing in accessories that enhance your pumping routine. For example, the Travel Cleaning Duo makes it easy to clean your pump parts on the go, ensuring you always have a hygienic setup. And if you’re planning to pump away from home, the Pump Anywhere Bag keeps your pump and accessories organized and discreet.

Pump Anywhere Bag

Pump Anywhere Bag

  • Hand wash inserts in warm soapy water
  • Air dry completely before storing
  • Use a dedicated cleaning kit for convenience

Maximizing Your Pumping Experience

Once you’ve mastered the insert set, you can further optimize your pumping sessions. Consider using a breast therapy pack before pumping to encourage let-down, or a natural pumping spray to lubricate the flange and reduce friction. These small additions can make a big difference in comfort and output.

Remember, every mother’s body is unique, so don’t be afraid to experiment with different sizes and techniques. The goal is to find what feels comfortable and efficient for you. With the right fit, your Willow pump becomes a reliable partner in your breastfeeding journey.

  • Warm compresses can help with let-down
  • Lubricating sprays reduce friction
  • Keep a pumping log to track what works

Achieving a perfect fit with your Willow pump is a game-changer for comfort and milk production. By using the Willow Sizing Insert Set correctly, you can avoid common pitfalls and enjoy a more effective pumping experience. Explore our range of accessories, including the Willow Go® Replacement Parts Set, to keep your pump in top condition. Happy pumping!