Flange-Shield Size Information

What is a breast pump flange/shield and why is getting the correct size important?

A breast pump flange is the plastic piece that fits around your areola, over your nipple to form a seal to create the vacuum needed for milk extraction. The flange is also known as a breast shield. Incorrect sized flanges can impact milk production, cause pain and nipple damage with milk expression. A shield too small or too large can impact the amount of milk you are able to pump and can cause concerns for your milk supply. You might find one breast or nipple a different size than the other, you may need two different sizes, one for each breast. One size doesn’t fit all, we are all unique.

How do you choose the correct size flange/breast shield for your nipple?

How To

Use a ruler or measuring tape and measure the distance straight across the middle of your nipple at the base (the diameter) don’t include the areola. I cm =10 mm

Choose the optimal size based on your nipple.

Based on your measurements follow the chart below for common Flange/Breast shield size. Please check with the manufacturer of your breast pump for available flange sizes. A few common flange/breast shield sizes are listed below. If you have questions about this, please contact our Lactation Consultant. Keep in mind your nipple can change in size during pregnancy, with pumping and or breastfeeding.

Not all brands have the same sizes these are Medela specific sizes.

21 mm flange/shield=nipple measurements up to 17mm

24 mm flange/shield=nipple measurements up to 20 mm

27 mm flange/shield=nipple measurements up to 23 mm

30 mm flange/shield=nipple measurements up to 26 mm

36 mm flange/shield=nipple measurements up to 36 mm

Select the size

Once you have selected your Breast pump check with the pump manufacturer to see what breast shield/flange size is included. If your size isn’t included with your pump be sure to order a flange-shield that is right fit for you.

How to try out your shield/flange size and decide what vacuum level (suction) is best for you?

How to...

Center your nipple and hold your breast shield/flange against your breast. Avoid pressing too hard.

Turn on the breast pump and adjust the vacuum level (suction). Turn the suction up until you feel a strong pull or slight discomfort and then turn down a notch or a few for optimal comfort. Turning up the suction too high can cause pain and sore nipples.

If your shield/flange fits correctly your nipple will be centered in the flange tunnel and will move freely without rubbing against the flange.

The information provided is not a substitute for medical advice or care. Please contact your Lactation Consultant or Primary Care Provider for breastfeeding and pumping concerns.