Breast Milk Storage Capacity 101: A Simple Guide for Breastfeeding Moms!

There are so many little things to learn about breastfeeding that can sometimes begin to feel overwhelming! Have no fear, we are here to help inform you in the least intimidating way possible 🙂 This article will cover breast storage capacity, what it is, why it matters, and how to find out your personal capacity!

The ability to produce breast milk is so individual from mom to mom. All breasts are different and their ability to produce breast milk can be different based on their storage capacity.

Storage capacity is a reason why we shouldn’t tell moms their baby should only eat every X amount of hours because it can vary from mom to mom. This can be a confusing topic, so let’s dive deep into breast milk storage capacity to help you optimize how you are feeding your baby!

What is “breast storage capacity?”

Breast storage capacity is the amount of milk that each of your breasts can hold at full capacity. Each woman has a different breast storage capacity regardless of the size of their breasts.

For example, a woman with DDD breasts may have a smaller breast storage capacity than a woman with A-cup breasts.

My favorite analogy I found while researching is to think of each woman as having her own measuring cup! Some women’s measuring cups are for 6 ounces, while others might be for 3 ounces. This is why some women may be able to produce a large amount of milk and not experience engorgement or clogged ducts, while other women with smaller capacities may experience these issues more often.

Each breast can have a different capacity as well!

With all this said – a woman with a small capacity can nurse just as successfully as a woman with a large capacity. She may need to nurse or pump more frequently for her baby to thrive – she will need to free up that space in the breasts so more milk can be produced. This study found that mothers with smaller storage capacity still resulted in babies with healthy weight gain.

The more frequently milk is removed, the faster that milk production becomes. This is especially important for mothers with lower storage capacity to understand. According to this document:

“Within a day, and even from feeding to feed, rate of milk production can change dramatically. In one study, for example, after 6 hours without milk removal, one mother’s rate of milk production per breast was 22 ml per hour. By breastfeeding from that breast every 90 minutes and removing milk from her breasts more completely, her rate of production per breast increased quickly within the same day to 56 ml per hour – more than double the previous rate.

When a mother reaches her storage capacity, if the milk isn’t removed, her baby tells the “milk-making factory” to slow down production. A mother with a large storage capacity may not reach that point as quickly, so it may take longer

Mothers with a large capacity may nurse less frequently, sometimes their baby will sleep longer at night (not always), etc. simply because they have more milk available at a feeding.

A woman with a large storage capacity may also be able to go longer without pumping or nursing and it does not impact her supply. This is one of the biggest reasons behind some women saying they didn’t notice any decrease in supply when they skipped a nursing or pumping session, while another mom saw an immediate impact.

One thing to keep in mind is that as your baby nurses and takes in the milk that is available, the body signals to make milk. So as your baby nurses, more milk might be produced and replace that milk that is being removed.

Do I have to wait for my breasts to fill back up?

When discussing storage capacity, it might make you feel like you have to wait for your breasts to “fill back up” and reach capacity. While yes, overtime your breasts may feel more full, you don’t have wait any period of time for them to be filled. Waiting for them to be fuller actually will tell your breasts to make less milk. Once there is stimulation at the breast, that tells them to start making more milk – so even if they don’t feel overly filled, your body will know to start making milk. And, as mentioned previously, the more stimulation and emptying of the breast, the faster the refill rate is.

What Determines Breast Storage Capacity?

This is the amount of available milk your breast for your baby when it’s at its fullest.

It all depends on how many mammary glands (lobules/ducts) your breasts have. Some women have more, some less. There are situations – such as women who have Insufficient Glandular Tissue or who have had previous breast surgery – where there may not be enough to produce a full supply of milk. If you are struggling with a low milk supply, make sure you reach out to a lactation professional to come up with a plan for you.

In the beginning weeks of breastfeeding, it’s important to follow your baby’s feeding cues so they can activate all the milk ducts and tell your baby to make milk. As the breast is emptied of its “capacity”, it signals to your body to speed up the production of breast milk. If your breasts aren’t being emptied frequently (especially in those early weeks and days), it may make it harder for your breasts to produce the highest capacity of milk.

So if women can breastfeed despite their breast storage capacity- why does it matter? This number matters because it helps a woman determine how often she needs to nurse her baby in order to make sure they get the proper amount of milk to thrive.

This is why you really can’t say “Babies should only eat every three hours” – because sometimes, a baby will NOT thrive on that frequency of feeding. It’s why some babies might wake more frequently to eat, or why some babies can go longer.

It is so individual for the mom and baby.

If you have a storage capacity of 3 ounces, you will likely need to feed your baby 9-12 times a day. If you have a higher storage capacity of say, 8 ounces, you would likely only need to feed your baby 5 times a day. Don’t be discouraged at your capacity, everybody is made differently and your babies will love your boobies and appreciate the milk no matter what 🙂

How do you find out WHAT your breast storage capacity is?

In order to begin the whole process of knowing how often you need to feed your baby, the first thing you need to know is what your personal capacity is!

I don’t recommend pumping as a way to determine your breast storage capacity, simply because pumping is not always indicative of how much milk you are making. Instead, I prefer learning about “The Magic Number”.

The ‘Magic Number’

The magic number by Nancy Mohrbacher is another tool that may be helpful to you as you learn about breast storage capacity and how it all works! I prefer this method over the firs

Morbracher’s ‘magic number’ refers to the number of times per day you need to breastfeed or pump in order to keep your milk production at the maximum level.

I recommend reading her article as it has tons of great information, but basically, you should think of a time when you were producing enough milk – you were comfortable, your baby was gaining weight well, and everything seemed to be going well. Determine how many times you were emptying your breasts at that time, and that is your ‘magic number’.

As explained above, because breastfeeding amounts per day vary on your capacity, this magic number will also vary. If you begin to drop below your “magic number” of feedings, you will find that your milk supply will also decrease.

Can you change your storage capacity?

Because storage capacity is based on your glandular tissue, it actually can change – but this is typically due to having more babies.

With each pregnancy, your body produces more glandular tissue. You don’t lose the glandular tissue you’ve developed previously, so most of the time if you produced enough milk for one baby, you generally will produce enough (and even more) with additional pregnancies. There are always exceptions to this, such as if there is a retained placenta or massive blood loss after pregnancy.

This can give hope to people who may not have produced enough milk before. Some moms – even those with IGT – find they are able to produce more milk with subsequent pregnancies.

One supplement that people believe can impact glandular tissue is Goat’s Rue, which is a commonly recommended galactagogue. According to the National Center for Biotechnology Information (NCBI), “No scientifically valid clinical trials support this use, although some old, poorly controlled studies found an effect.”

It should not be the only method for increasing milk supply, but many mothers do report that they feel it helped them increase their storage capacity.

NCBI also says, “Though it has a long history of use as a galactagogue, very limited scientific data exist on the safety and efficacy of goat’s rue in nursing mothers or infants. In general, goat’s rue is well-tolerated, but it might cause hypoglycemia, so caution should be used in women taking antidiabetic drugs. Diarrhea and hepatomegaly occurred in a woman taking fennel, fenugreek, and goat’s rue as galactagogues.”

You can buy Goat’s Rue on its own, but I have heard good things about Liquid Gold from Legendairy Milk. It’s a high-quality supplement that I know a lot of moms have good success with.

What are the Different Storage Capacities

You might be asking yourself, “So do I have a low, medium, or large storage capacity?” Which is a good question. Here is a general guide to determining what size your storage capacity is (graphic from Nancy Mohrbacher):

Remember that none of this information is meant to overwhelm you, but to help inform you more about your body and how to best provide for your little bundle of joy! Knowing your breast storage capacity can be such a helpful part of creating a breastfeeding or pumping schedule and keeping your baby well-fed and your body healthy.

More Blog Posts You Might Enjoy:

• Breastfeeding Your Newborn Baby: What All New Parents Should Know
• When Does Milk Come in? 8 Secrets for Establishing Milk Supply
• The Best Foods to Help Increase Milk Supply