Breast Shield Sizing Guide

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This is part 2 of ‘How to Pump Breast Milk Efficiently’ series. In the previous article I’ve discuss things you should know even before start pumping. Now let’s move ahead and discuss about how to get correctly-fitted breast shield.

Do you know that getting a correctly-fitted breast shield is crucial if you pump breast milk?

Here are the reasons:

• Incorrect breast shield makes pumping uncomfortable (or in some cases, painful). This is especially true if you are using breast shield that is too small.
• Not optimal pumping output. With incorrectly size shield, you pump less milk. Yes, this is true. In my experience, getting correctly fitted breast shield may increase the pumping yield up to 20%.

So now, how to make sure you got the correct breast shield? In this article, I share my insights on how to choose properly fitted breast shield and my personal experience that proper fitting does matter a lot. Read further to know more.

(This is NOT a sponsored post. All products mentioned here were bought out of necessities . This post contains affiliate links)

There are a lot of guidelines and infographics about how to choose the correct breast shield, but my favorite is Medela breast shield sizing guide. It provides good illustration and great infographics. Maymom, on the other hand, provides FREE nipple caliper printable for download.

Medela mentioned to choose breast shield with inner diameter 4 mm more than your nipple diameter. Whereas Maymom mention 2-3 mm.

Personally I follow Medela guidelines in choosing my initial breast shield size, because it is simply clearer.

However, you should not follow this guideline blindly because the info graphic merely relies on nipple diameter only. In addition to nipple diameter, you should also consider the following factors:

• Check how your nipple moves while pumping.

The nipple should move freely and it should not rub the side wall of the flange. You may see a little bit of areola gets pulled, but not the whole areola. And your nipple should not hit the back wall of the breast shield.

• Comfort

Even if you think you already choose the best breast shield size, but you feel uncomfortable / painful while pumping, that means something is not right. Try to size up or down. Nipple redness / or sore feeling after pumping is also an alarm that you may need to choose different breast shield size.

• Effectiveness of pumping

If you feel you breast is not emptied after pumping, you may suspect that you don’t use the correct breast shield size (note: various factors can affect this, breast shield size is just one of possible reason).

• Breast tissue / elasticity

Some women has a very elastic tissue so that the skin will get pulled easier. In this case, it is possible that pumping makes nipple get elongated so much until it hits the back wall of the flange. For this case, using breast shield with longer ‘tunnel’, or using smaller insert in bigger breast shield may help.

• Suction preference matters

The stronger the suction you use during pumping, the more your nipple will be pulled into the tunnel. And there is higher chance to hit the back wall of the tunnel if you have quite elastic tissue. In this case, using ‘insert’ would be best approach to use.

IMPORTANT!

• Your left nipple diameter may not be the same with your right nipple diameter, and thus may require different breast shield size.
• Your nipple diameter may change (enlarge a little bit) during pumping session. I think that’s why Medela guidelines add extra 4 mm to determine your breast shield size from the actual nipple diameter. I think this ‘diameter’ refers to nipple diameter before pumping.
  

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How I found my correct breast shield size

When I purchased my Medela breast pump, i refer to Medela guidelines to determine my correct breast shield size.

Based on nipple diameter alone, it would be the 21-mm size (size S). So in addition to the standard 24-mm shield (size M) I purchase the 21-mm one.

My mistake: 

I didn’t compare from the beginning between using the two sizes. I used size S straight away, and use the maximum comfortable suction level I could.

Honestly, back then, I was not impressed by my Medela performance because it didn’t really empty my breast fully. But I thought that’s just how electric breast pump is.

One day, I decided to use the standard flange, and to my surprise, I got more milk. At that time I felt like dumb for not trying it from the very beginning.

I began using size M from that point onward, until I decided to try a new breast pump.  Again, conversation with seller pointed me to the Medela guide again and I started wondering why this guide didn’t work for me.

My new pump had a flange diameter of 25 mm and I could feel that it was not extracting milk efficiently.

My nipple was constantly hitting the back wall of the flange. Not, it was not painful, but the suction become less efficient.

So I tried experimenting with different flange size, including attaching Medela 21-mm inside the original Spectra flange (yes, seriously I did that). And it works much better, but not so convenient.

So I searched for better option when I stumbled upon ‘breast shield insert‘. Aha, I think this is the one that I need. So bought a pair from my local retailer and totally in love with it.

Here’s how it looks like. It says Medela 21-mm insert (NOT 21-mm breast shield, they are different!)
The advantage of using insert vs breast shield is you get a much longer tunnel length, so nipple won’t easily hit the back wall of the flanges even in highest suction setting.

And you know what? Once I switch to using my new ‘breast shield system’, which essentially using a 21-mm insert inside a standard breast shield, my pumping yield increases up to 20%. Whoaa… I wish I figured this out much earlier..

So, again, I strongly recommend you to compare several breast shield size right at the beginning, especially if you have not found a good fit with the standard size that comes with the pump.

If your pump does not come with a variety of breast shield size, do try Maymom breast shields. Maymom is not breast pump brand, but it offers compatible breast shield of various sizes for Medela, Ameda, and Spectra.

For Medela-compatible breast shields, it has 11 different sizes: 15, 17, 19, 21, 24, 25, 27, 29, 30, 34,36 mm, and additionally 22-mm insert (to be used with 25-mm flange) and 28-mm insert (to be used with 30-mm flange). Quite a whole lot of variety to choose from.

Other moms’ stories

Now that you’ve heard my story, I wanted to share some of my readers’ story who managed to avoid pain while pumping and have increased their pumping output by using the correctly-fitted breast shield.

Aida has recently shared her success on increasing her pumping output after switching to a smaller breast shield.

Here’s what she said:

It’s really true! Correct flange size will give better output. My first baby is almost 3 months. I have no deep knowledge about breast milk since this is my first baby.

I really dig the info because I wonder how other people can make it, how to breastfeed my baby till 2 years if everytime I pump I feel pain and sore. Then only I know how to measure my nipple and choose the right flange size.

From flange size of 28 mm, I changed to 24 mm, and now 21 mm. It really hurts when I pump using 28mm breast shield because it also pulls quite big range of my alveolar. Now, no more pain. .

(look at the pic) After 20mins pumping, my baby woke up. I direct fed my baby and continued to pump the other side to complete 30mins. Before this most yield is 3 oz each side. Thats the max, normally it is less than that, hahaha.

FYI, I’m using Spectra and Maymom 21-mm breast shield.

Rina’s comment:  from 3 oz each side to 3.5 – 4.8 oz, wow.. that’s a huge increase, congrats, Aida.

Another reader, Linda, shared that after using the 21-mm insert, she managed to increase her pumping output.

I just bought “Medela breast shield 21-mm insert.” It fits Spectra 24-mm flange too, or if you use Medela, fits in 24-mm flange. I’m using both. I also used hospital grade Spectra breast pump (i.e Spectra S1). Guess what? My output is 150% up (compared to my yield when I pumped for my first born)!

So, if you haven’t tried to really measure your correct breast shield diameter, you should do this. Correctly-fit breast shield leads to more milk, proven!

Now, if you have tried several sizes and you feel that your pumping yield is not optimal, or the way your nipple moves back and forth does not feel comfortable, you may try using Pumpin Pals flange.

June shared that she experienced nipple pain and ‘hitting the back wall’ problem with her original flange size.

Well, I tried both the 30-mm and 24-mm Maymom breast shield and one too large while the other too small. So my original size of 27-28-mm is correct, just that my tissue is elastic.

In the end I bought Pumpin pals and that seemed to solve the problem of hitting the back wall.

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Now, let’s summarize what we learned here.

To choose the correct breast shield size, there are a few things to consider:

• Nipple diameter (follow Medela guidelines)
• Comfort (discomfort means something wrong)
• Suction preference (higher suction: may need longer breast shield tunnel)
• Breast tissue elasticity (more elastic: longer breast shield tunnel)
• Effectiveness of pumping (more milk with correct breast shield size)

If you feel that your breast pump brand does not cover a wide-variety of breast shield sizes, here’s some recommended accessories that may help:

• Maymom breast shield: covering breast shield diameter from 15-36 mm (plus 22-mm and 28-mm inserts)
• Pumpin Pals super shield: 3-size angled breast shield that promotes pain-free pumping and no need to leaning forward while pumping.

I hope this article will help you to pick the correct breast shield size, and thus, able to pump more effectively.

If you have any questions, feel free to ask. I’m glad to help.

Now, my question to you: Have you tried various size of breast shields and picked the correct one for you? How was it? Do you think using correct breast shield can maximise your pumping output? Share your insights with us!

Are you struggling to pump enough milk?

This FREE pumping checklist summarizes my best pumping strategies that will help you pump effectively and get more milk!

Click here to download your pumping checklist