Breast Shield Sizing Guide

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This is part 2 of ‘Pumping 101’ 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.

There are a lot of guidelines and infographics about how to choose the correct breast shield, but three stand out.

Maymom nipple caliper printable

1. Medela breast shield sizing guide. It provides good illustration and great infographics.

2. Maymom breast shield sizing guide, which provides FREE nipple caliper printable for download.

3. Pumpables breast shield sizing guide, that also comes with FREE nipple ruler.

What are the differences between them?

Medela recommends choosing breast shield with inner diameter 4 mm more than your nipple diameter, whereas Maymom mentions 2-3 mm. For these two resources, my guess is to measure your nipple diameter before pumping.

Pumpables, on the other hand, clearly explained that it is best to measure your nipple diameter after pumping for 5 minutes.

Having tried those resources, I personally prefer Pumpables guide because it is pretty straight forward and the nipple ruler is also easy to use. However, if you have not pumped before (say, still pregnant), I guess Medela or Maymom guide will work better for you to get initial estimate. Remember though, once you start breastfeeding or pumping, your nipple will change its diameter (thus the additional few mm added).

Pumpables nipple ruler

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).

PS: Check out this article for more in-depth explanation for nipple pains while pumping (includes reasons and solution).

• 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. More discussion about this below.

• 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.
• As you pump regularly, your nipple diameter may change again. So it’s best to reassess your breast shield size every few months.
  

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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 purchased 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.

RELATED: 10 Tips to Pump Breast Milk Faster

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!

Let’s talk about tissue elasticity now.

When your breast tissue has higher elasticity, the tip of your nipple may extend all the way towards the end of the tunnel, no matter which size you use. In addition to choosing breast shield with longer tunnel or using insert,  you may also choose soft silicone flange instead of hard-plastic flange. The silicone flange may help giving more grip to hold your areola so that it won’t extend too much.

Click here to find out the most popular silicon breast pump flange and cushions that pumping moms love. I also included the pros and cons for each of them and how to choose the best one for your need. PS: My favorite is #2.

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 Pumpables/ Medela / Maymom guidelines)
• Comfort (discomfort means something wrong)
• Suction preference (higher suction: the nipple may swell more or you may need longer breast shield tunnel)
• Breast tissue elasticity (more elastic: longer breast shield tunnel or need to opt for silicon flanges / insert)
• 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 are some recommended accessories that may help:

• Maymom breast shield: covering breast shield diameter from 15-36 mm (plus 22-mm and 28-mm inserts), also those compatible with Spectra
• Pumpin Pals super shield: 3-size angled breast shield that promotes pain-free pumping and no need to leaning forward while pumping.
• Inserts for those needing smaller diameter but longer tunnel: Maymom has produced both hard and soft silicon inserts of various sizes (the soft ones can be used for hands-free collection cup and wearable breast pump such as Elvie and Willow, too) .

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

Still need help in deciding your perfect breast shield size? You may check out:

1. Pumpable fitting room ( FREE consultation with Pumpables team, send your pumping video over and let them share their suggestion)
2. Online consultation with lactation consultants (a short video consultation for a small fee, such as this).

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!

NEXT IN THE SERIES: 10 Ways to Stimulate Let-Down While Pumping