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Pumping Mistakes that can Decrease Milk Supply

You would be surprised how many of us moms are doing things that they think are helping their milk supply, but are actually hurting? Myself included, I had no idea! It's unbelievably common.

Flanges are not one size fits all, you can't just crank the pump up to 12, and those magic pills might be a waste of money!

In this post I will cover some common mistakes, issues, and misconceptions that may result in decreased milk supply, rather than the desired increase!

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I am a Certified Breastfeeding Specialist. However, the advice and tips on my pages is not personalized individual medical advice and you should always discuss concerns with your healthcare provider or seek the help of a lactation professional. I do not currently offer consults or counseling, just general information and advice.


I could not believe how many things that I was doing that actually took chunks out of my milk supply. Keep in mind I exclusively pumped, so I don't have any personal experience with nursing or combo between nursing and pumping. Update: with my third baby, I do combo feed nursing/pumping and pumping for the toddler. But I exclusively pumped for over a year with my second child.

Did you know that all those photos you see online of filled-to-the-brim pump bottles are NOT what a regular pump session looks like? In fact, they're extremely abnormal. I found that pumping an ounce per side per hour is even a large oversupply for a single baby. So for example if you pump every 2 hours, and see your pump session is yielding 4 ounces in total, you'd be producing 48 ounces a day?!

Do you know how much the average baby eats in a day? Far less than that! I've heard they eat around an ounce an hour (past the newborn phase of course) when they're not having growth spurts or anything.

Keep in mind that ounces add up, even though they don't look like much when you're pumping into a 6 or more ounce capacity bottle.

Compare that to how much a baby eats during the first month.. you'll feel a lot better about it.

Between the ages of 1-6 months, breastfed babies will typically drink on average 25 ounces (750ml) of milk per day. So producing an ounce per hour is right about on par with that.. can you believe that?! If you're producing more than baby eats even by an ounce, it's considered an oversupply! And to think it doesn't look like much in the bottles.

Newborn Stomach Capacity

Those photos you see online with full pump bottles, that's almost NEVER a regular session! (with the exclusion of women with a huge oversupply)

These photos are from 9 months into my exclusive pumping journey.

On the left is what I pumped first thing in the morning after going a 10 hour gap without pumping. I only did this because I'd had a regulated supply for many many months, and eased into that amount of hourly gap. I do not recommend anyone to try going that long when you're a newer pumper. (first 12 weeks or so).

On the right is what I produce if I pump more often, like every 2 or 3 hours. It looks like nothing in those huge bottles! If you do the math, 60ml every 2 hours, if you pump that literally 12 times a day, is 48 ounces! For a baby drinking 25 in a day, you could almost feed two of them. Your ounces add up!


Not pumping often enough

Milk is produced on a supply and demand basis. You will replace what you remove, and what's left unused is taken as a sign that you didn't need it. Stagnant milk builds up Feedback Inhibitor of Lactation- FIL for short, and this buildup of FIL tells the milk factory to slow down production. If you're pumping often and the FIL doesn't build up, the factory runs at full speed.

If you aren't pumping as often as baby feeds, or just pumping "whenever you feel full", you're telling your body that you don't need as much milk and your body will read this as a sign to produce less.

You have to pump each time baby feeds, as a signal for your body to replace what was just eaten. You can even pump more than that to ask for more milk.

A "power pump" is a handy trick used by lots of moms to essentially 'place an order' for more milk.

Here's an infographic on power pumping from my friends over at Legendairy Milk -

Power Pumping how to chart by legendairy milk
via Legendairy Milk


Not pumping long enough

You have to be very sure to pump until empty (or longer, to ask your body for more milk) almost every single time. You're never truly 100% empty, but you can get majority of it out.

As I briefly mentioned before, milk that's left behind or stagnant will build up FIL (feedback inhibitor of lactation) which is a signal to the milk factory to slow down production.

I have typically never pumped less than 20 minutes. When my baby was born, I pumped every 2 hours for 20 minutes each time. Then I moved to every 3 hours, 30 minutes each time, to every 4 hours 40 minutes each time, and my first pump of the day now after sleeping all night is typically an hour. (I'm 9 months postpartum right now when this is first published)

Everyone has different "times to empty" but typically that means your breasts are feeling softer, and no more milk comes out for a few minutes during pumping. This can be mistaken for the time between letdowns, so I like to give myself quite a bit of time to be sure. I've had letdowns as far apart as 15 minutes! note "empty" is a loaded word, we are never TRULY empty.


Pumping with the wrong parts or settings

If you use the wrong sized flanges, you'll experience a few things. None of them good!

First will be pain, from either too small or too large. If they're too small, your entire nipple doesn't fit into the flange and it may get blisters, cuts, "road rash", and in turn will not be able to properly remove milk. If they're too large, too much of the areola will get sucked in, swell up, and can constrict the "tubes" where milk flows through and you won't be able to properly remove milk.

Flange Fit During Pumping Guide
via Aeroflow Breastpumps

How to measure? Use either a printable ruler like my free one here, or purchase a silicone/plastic ruler like this one here. I recommend measuring before pumping, especially if you've been pumping with a large size that's caused swelling to your nipples.

Silicone Nipple Ruler for Flange Measurement
via Legendairy Milk

On top of that, it HURTS to use the wrong size, and when you're in pain, you can't relax and have a proper milk let down. Milk let down is best when you're relaxed. If you're gripping the sides of the chair with white knuckles because of how bad the first two minutes of pumping hurt, you may have a tough time getting a letdown.

You need to measure your nipples to ensure the correct flange fit. Did you know, the standard flanges that come in the box with pumps, are typically NOT the correct size? According to my friends at Pumpables, 17mm is the most common size. In pump boxes, you typically receive a 24mm and a 28mm. Using a flange almost 10mm too big is crazy! I think that the brands do this because you can kinda use one that's too big, but you absolutely cannot use one that's too small.

Your nipple size may change, by the way. In a matter of three months, I went from 19mm to 17mm to 15mm!

Pumpables vs Legendairy Milk Nipple Rulers
Pumpables vs Legendairy Milk Nipple Rulers

A note on these rulers - Someone posted in one of the groups I'm in asking if these two measured the same. A commenter insisted that they did not, that pumpables was 2-3mm larger than others. I feel that this person may have printed the pumpables ruler in an image format rather than the PDF which is the correct size. As you can see, they only have 3 common measurements- all of which are exactly identical. Both of these are accurate measuring tools.

Did you know there are soft silicone flanges out there? I couldn't believe how good it felt to try those for the first time. Especially if you have elastic nipples, silicone flanges are a lifesaver. I have used and enjoy the Pumpables Liquid Shields, Lacteck flanges, and Pumpin Pals flanges. See my full post on different breast pump flanges here!

Note: if you purchase any of these, be sure you have the full setup to use them. They don't always fit into your stock pump parts.

For Pumpables that would be the Liquid Shield Kit (this is one piece, be sure to get two! total cost for both is about $60)

For Lacteck that would be an adapter piece that fits onto whatever brand pump you're using (I purchased a maymom adapter piece to fit my Spectra parts) Update October 2022- I have been using and loving the PumpinPal XS flanges (about 15mm). These also require that maymom adapter and a special collar piece (pumpinpal has them).

Pumpables Liquid Insert Soft Flanges
Pumpables Liquid Insert

Lacteck BabyMotion Flanges
Lacteck Babymotion Flanges


More suction does NOT equal more milk.

I cannot believe I've seen people genuinely recommend to "work up to the strongest suction on your pump." No way! Do not do that! I've used 5 or 6 as the highest level, and it works perfectly fine each time for me. My friend however, uses around 9 or 10 with no issues. Everyone is different!

Using too high of suction can cause damage to your nipples, make them swell, disrupt milk flow, and just hurt!

Using too low can cause emptying to take longer, be less efficient, and maybe leave milk behind as well. Remember what I said about milk left behind?

You want to have it "as high as is comfortable", according to a few moms I've spoken to. If it starts to hurt, turn it back down. Out of 12 total suction levels on spectra, 6 is still very powerful for me.


Using the wrong kind of pump

As convenient and amazing as wearable pumps are, they are not recommended for full time, primary use. Some women - I call them unicorns - can get away with using them alone, and get their full output daily. Unfortunately that's not always the case, and most of the time these wearable pumps (especially the super cheap ones you can find on Amazon) don't empty well or pull enough milk efficiently, which will send your body the message that there's milk leftover, and it's not needed.

As I mentioned before, unused milk is a message to the body that you need LESS milk produced.

Wearable pumps are a great option to have, for occasional use. I personally got a few pairs of cups (to plug into my main pump) and I purchased the Imani I2 wearable pumps from Legendairy milk (which worked decent about half the time I found) and I was gifted an Elvie Stride from a friend that I couldn't get to work properly, even trying just the cups with my regular pump. I found the Legendairy milk cups to be decent some of the time as well, but not every time. It was truly so frustrating. I've tried a few more wearables since then and while I have some that work better than others, they are definitely not my primary pumps.

Wall plug pumps are typically seen as the most "powerful" and "beefy" pumps out there, which I can mostly agree with. However, I know very few moms who can afford to sit plugged in for hours a day. So to survive, we have to go with portable options.

There are small, portable pumps that have saved countless pumping journeys due to their convenience and providing the ability to pump while walking, cleaning, driving, and working.

With my exclusive pumping journey, my two primary pumps were the Pumpables Genie Advanced and the Spectra Synergy Gold. With my third journey (still on it as of this update Feb 2024) my two primaries are the Unimom Opera and Baby Buddha, but I do still love those two previous pumps as well.

Here's a side by side comparison of my first two main breast pumps:

Spectra Synergy Gold vs Pumpables Genie Advanced

Note that the Genie Advanced, while smaller than the Spectra Gold, has a higher max vacuum.


Wearable collection cups are also a great option to have, but not for regular use.

Wearable collection cups are a portable pumping accessory, relatively discreet, but still have tubing. Typically this can be tucked into your shirt to be out of the way. Keep in mind if you're shopping for a 100% discreet and silent pumping option that can be used full time, you might just be disappointed.

I personally used the Legendairy Milk Collection Cups from time to time, like when we would drive somewhere and I have to pump in the car. However I did find that more often than not, the cups didn't work as well as the flanges and I would opt for those instead.

They can be a good option to have when you need to clean the house without getting smacked on every doorknob or want to go out of the house and not have the world looking at your nipples! Tuck the tubes under your shirt if they get in the way.

You can even carry your baby around easier while wearing these compared to standard flange kits. I'd carried both of my kids (3 year old and 9 month old) to the bathtub and back while pumping.

Update October 2022- the Imani i2 cups (minus the motors) have a lot better suction in my opinion. See my reel on that here

Update Feb 2024- I've been experimenting with a lot of cups over the years, I was informed after purchasing the Baby Buddha cups (which are identical to Zomee cups) that if you boil the parts before the first use, they 'seal better'. I did that, and it seems to make a difference compared to the other parts I did not boil before first use. I'm still testing more but so far that seems to be something.


You're relying on too many magic pills

There are so many supplements out there that promise to increase milk supply.

We've all seen those advertisements with 8 ounce milk bottles next to a 2 ounce bottle stating "My milk supply went from this to this overnight!"

Yeah, that's usually a cash grab. Do your research! Read reviews of these products on websites OTHER than the ones they're listed on.

Some of them certainly work for some women, and some of them do not. Personally I can eat lactation cookies with things like flaxseed, brewers yeast and oatmeal and see a rise in milk supply. Not gallons, of course, but a noticeable difference. I do accredit most of that to the calories though, probably.

If I take fenugreek, one of the most popular supplements, my supply is cut nearly in half. Some supplements have adverse effects on supply, and that's normal. Not everything works for everyone. If you have a thyroid condition, fenugreek may cause trouble for you! A lot of women who see a decrease from fenugreek have a thyroid condition. I do not, at least not that has been diagnosed. Always ask your primary care provider before using supplements.

Don't load up on every promising supplement on the market thinking you're gonna pump 8 ounce sessions 7 times a day! Try them one at a time, and see which ones do what to your supply. But proceed with caution! As mentioned previously, always ask your primary care provider.

That said, there are lots of lactogenic foods out there that are proven (in some cases) to increase milk supply in both animals and humans. Barley, for example, is high in beta glucans, which can increase the production and circulation of prolactin, which can in turn increase milk production.


Your parts are old or wearing out

Every part that comes with your pump that's soft or silicone will need to be replaced at some point. Some more often than others.

When they begin to wear out and lose their "crispiness" as I like to call it, the suction will decrease, remove less milk, and you'll produce less milk.

I advise moms to keep a spare of EVERY part of your pump at ALL TIMES. It'll be just your luck that your duckbill gets dropped in the garbage disposal, or the cat gets your tubing, and you're outta luck until the Amazon Prime Fairy can drop you a new one in two days.

In my personal experience, this is how often I typically find that I need to replace something. Note: the "silicone flange" I refer to is something like a pumpables liquid insert- lacteck and pumpin pals last way longer and are usually not needing to be replaced unless they get damaged.

Replace every month ( 4+ pumps a day)

Replace "every six months" according to manufacturers, but really "if damaged"

Not necessary to replace unless damaged

Replace frequently with exclusive use (4+ pumps a day). approx 2-3 weeks

Duckbills or Membranes

Hard plastic flange

Silicone flange inserts such as maymom etc

"liquid flange inserts" such as pumpables, legendairy milk

JUST the silicone from backflow protectors. Plastic is fine.


Silicone solid flanges such as pumpin pals, lacteck etc

Plastic/glass collection bottles or cups

Tubing adapters or collection cup caps etc.


You're not eating or drinking enough

Did you know that breastfeeding burns extra calories? I am 100% convinced that doesn't help us lose any weight, but instead we starve like we haven't eaten in days.

To replace that extra burn, you have to eat a little more than a non breastfeeding person. Typically it's only 500-800 calories that you burn, but it differs from person to person based on body type and mass. I've read around 20 calories per ounce of milk produced.

The Lactation Nutritionalist has a neat calculator that tells you how many calories you need to consume to maintain milk supply, lose weight, or maintain weight. This may or may not be 100% accurate.

If you're not keeping up enough calories, you can't produce as much milk. The same goes for staying hydrated.

I like to aim to drink half of my body weight in ounces of water per day, which equals about 70 ounces, or about 4 and a half regular sized water bottles. But just like the hunger, I'm seemingly constantly parched and am guzzling more than that.

Make sure you don't overdo the water though, you can cover up your natural feeling of hunger and then in turn not consume enough calories!

I also sometimes have an electrolyte beverage a day, people call Bodyarmor/gatorade and coconut water "milk supply increasers" but really you're just likely lacking in electrolytes and dehydrated. When fully hydrated and your electrolytes topped up, you can produce the proper amount of milk your body is able to (without underlying issues of course)

Anna Pelzer | Unsplash

I read before that "to lose weight breastfeeding, you should try to just make sure you're eating full meals with real foods like fruits, vegetables, whole grains, and lean meats". But that's much easier said than done, and prepackaged foods often find their way into a busy mom's mouth! I personally eat whatever I can get my hands on, I have no time to prep fancy stuff for myself.


You're too stressed

Believe it or not, stress and relaxation both play a part in milk production and ejection reflex.

I'll sum it up in a brief explanation, which may not be 100% scientifically accurate but it's the way I remember it being explained to me.

When you relax, such as during sleep, your body produces a hormone called prolactin. This hormone not only produces milk but aids in letdowns, which is why it's so highly encouraged to "relax" when you're pumping. Thinking of waterfalls, looking at pictures of your baby, etc. Oxytocin, the happiness hormone, also plays a big part in milk letdown. A rush of oxytocin causes muscles in the breast to contract and squeeze milk out of the glands and ducts.

When you're stressed, anxious, scared, etc you can't get a proper letdown.

"Stress is the No. 1 killer of breastmilk supply, especially in the first few weeks after delivery. Between lack of sleep and adjusting to the baby’s schedule, rising levels of certain hormones such as cortisol can dramatically reduce your milk supply. I’ve seen women who, within 24 hours, have gone from having an ample milk supply to literally none due to stress." via Shivani Patel, MD, OBGYN

If I know I'm "about to be stressed out"- for example if everyone is screaming, and my pump alarm goes off, I'd sooner push my pump a bit than start trying to pump while my toddler is screaming "BINGO HAD A DOG, AND BINGO WAS HIS NAME-O! B, I, N, T, O, B, I, N, T, O" while the baby is crawling after her trying to get whatever she's holding, and the cat is meowing for food, and I'm hungry and my pants are too tight.

I always do my very best to pump in the most relaxing setting, otherwise in my brain it feels like I'm wasting my time trying to pump when I can't do it to the 'best of my ability'.

During pumping I like to do something to help keep me relaxed, such as eat a favorite snack or watch a Netflix show, if I'm able to. I'm actually pumping right now as I'm typing this, which is something else I enjoy doing, so I feel plenty relaxed. The kids have wandered off to find their dad in the next room, so there's no misspelled bingo action happening right now.

Another issue I see lots of moms have relating to stress, is stressing over how much milk they think they're not making. My advice: cover the bottles. I used baby socks for that, they work great.

Don't sit there watching drips, thinking "oh no, it's not enough it's not enough!". It's counterintuitive!

I recommend covering pump bottles with socks to try to alleviate some of the stress of watching.. Ever heard "a watched pot never boils"?


You're taking medications that tank your supply

Are you taking birth control with estrogen? Estrogen/progesterone may destroy your milk supply- this is actually a common way that some moms will find out they're expecting again. When you get pregnant, your estrogen/progesterone levels rise and your milk supply may tank. This doesn't happen to every mom, but it's very common. It happened to me with my third baby! That's actually the first sign I had of being pregnant again. Please note the "mini pill" is advertised as breastfeeding safe and isn't supposed to decrease supply, but I have spoken to moms that have had issues, so it seems like it's not the same across the board. When your doctor tells you "breastfeeding safe" it does NOT always equal "won't decrease supply". Benadryl, Sudafed, anything meant to dry up mucous membranes may also be detrimental to milk production. Here's a great post on breastfeeding safe cold medication from Pharmomacist on Instagram, I highly recommend following her.

When I had my second baby, I was c-vid positive and I had been given Sudafed for congestion.

Note that only after I got to the recovery room, the nurse over there mentioned that they probably shouldn't have given me that.

I feel that this may have contributed to her needing to be formula fed and then getting a flow preference and not being able to latch properly, which may have contributed to the start of our exclusive pumping journey.

Always double check prescription or non prescription medications before taking them, a good number of medications are actually 'safe' for breastfeeding but sometimes they are not, or have the potential to decrease supply. Resources for checking if a medication is safe to use for breastfeeding: e-lactancia

Please note some herbs such as fenugreek can have an adverse reaction and decrease supply when they're advertised only to increase. Please see this helpful post about Fenugreek, Thryoid problems, and breastfeeding from

For a personal example, I saw a detrimental decrease when trying fenugreek. I do not have any thyroid problems that I know about.


You're not sleeping enough

Prolactin, one of the milk making hormones, is produced the most while you sleep. So, if you're not sleeping enough, chances are you're not producing as much prolactin as you could be.

Sleep is extremely crucial not only in milk production, but in sanity! You can't run on fumes, let alone take care of the house, the kids, work, etc.

As a side note, your pump sessions will almost always have different amounts. Especially towards the end of the day, as prolactin levels taper out, so does the milk output. Don't worry when your last pump of the day is far less than the first, that's completely normal!

Middle of the night pumps can be extremely beneficial for a few extra ounces.


I hope that something on this list can help you have an easier time producing milk for your sweet baby. It's a very hard job, and feels like a constant uphill battle. But you've got this! It doesn't have to be impossible!

Sometimes, there are medical causes for low milk supply. If you have any reason to believe your milk supply is low due to any number of medical possibilities, I urge you to reach out to your OBGYN or IBCLC or both!

If you find that you're struggling to keep up with milk supply, please don't hesitate to reach out to a Lactation Professional, or a pumping group on websites like Facebook or Reddit.

Don't be hard on yourself because you don't know what to do, there are so many resources out there available to help you if you want it.

However, I do personally believe that if trying to keep up with the mental, emotional and physical demands of breastfeeding becomes too much, and you have exhausted all avenues, it's more than perfectly acceptable to throw in the towel. I've been there.

A mother needs her sanity more than anything, and everyone else needs mom to be in good shape too!

If you're nursing or pumping, consider taking a look at some of my other posts for some additional information:

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