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How to Choose Your Breast Pump Flange (Shield) Size

 Why Choosing the Right Flange Size is Important?

Breast flanges are sometimes also called breast shields. While comfort is often the driving determinant in figuring out the right size, using the correct sized breast flanges will also make your pumping more efficient. Pumping can be hard enough on its own but having an unfitting flange (shield) may impact the amount of milk you are able to pump. It’s good to keep in mind that the right breast shield size may change over the course of your pumping and nursing journey, so it’s a good idea to check occasionally you are still using the right size. Or you might find that your breasts need different flange sizes – that’s normal too. Remember, pumping shouldn’t hurt!

The starting point for choosing the correct breast flange is to determine your optimal size based on your nipple diameter.

how to measure nipple for flange size

Nipple size chart and the corresponding breast flange (shield) size: 

NIPPLE DIAMETER
BREAST PUMP FLANGE (SHIELD)
mm
 Suggested size
Up to 17mm
17mm - 20mm
20mm - 25mm

How to measure your flange size

Since your breast shield size is also dependent on breast tissue and skin elasticity, it’s important to confirm you’ve chosen the correct size. Here’s how to check:

  • Using the 24 mm breast flanges included with your pump (or the size chosen after measuring your nipples), centre your nipple and gently hold the breast flange against your breast.
  • Adjust your breast pump’s vacuum through stimulation all the way up to a slightly uncomfortable vacuum, and then down one notch.
  • When your breast flange (shield) fits correctly, your nipple will be centered in the breast shield tunnel and will move freely during pumping

Troubleshooting the breast pump flanges 

It’s worth resizing the shield if you struggle with the following:

  • Your nipple is rubbing the sides of the breast shield tunnel to the point of causing discomfort.
  • You see excessive areola being pulled into the breast shield tunnel.
  • You have redness on or at the base of the nipple during and/or after pumping.
  • Your nipples or areola are turning white during and/or after pumping.
  • Your breasts still feel full after pumping.

Note: Pressing the shields too hard against your breasts when pumping can block your milk ducts.

Shop Breast Pump Flange here (available in sizes 21mm, 24mm, and 27mm) or the Complete Breast Pump Spare Set here.