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Breast Milk Storage Capacity: What It Means and How To Measure It

breastfeeding babyBreastfeeding and sleep training really can go together — that’s something we believe strongly here at the Baby Sleep Site®! However, if you know for sure that your baby’s sleep and feeding schedules will complement each other, you first need to know approximately how much breast milk your body produces and stores.

About Breast Milk Storage

Some breasts look big on the outside but have small storage capacities on the inside. Others look small but can store a lot of milk, so it’s all about the amount of storage capacity inside the breast.

Think of your breasts like two measuring cups. Each woman has a different-sized set of measuring cups. In fact, some women find that each breast is a different size! Most women find when they pump that one breast will supply more milk than the other. For instance, one breast may provide 3 ounces and the other breast may provide 4 ounces.

How to Determine Your Storage Capacity

To determine how much milk your breasts store, you can pump your breasts when they feel full to find out how much milk your breasts can store at one time. Usually, you will get the most milk just before the first nursing of the day. To determine your storage capacity, pump first thing in the morning, 1-2 hours before your baby’s first feeding. You can then offer the pumped milk to your baby in a bottle at feeding time, or you can nurse here like normal when feeding time rolls around (since your milk supply will have had time to replenish.)

If pumping isn’t the best solution for you, you can have your baby weighed before and after a feeding by a nurse or lactation consultant. Many hospitals, lactation consultants, and clinics will do this for free. Babies take different amounts of milk at different feedings; so for an estimate of how much your breasts store at one time, weigh the baby before and after they’ve had one of their larger meals. Of course, your breasts are more like a river than a lake, in that the milk is constantly being made, but some breasts do store more at one time than others, and this will affect how often your baby needs to nurse.

If you want to pump in order to find out approximately how much milk your breasts hold, be sure to use a good, hospital-grade pump, like Spectra’s breast pump. You don’t necessarily have to buy this kind of pump; you can check with your local hospital about borrowing one. Nicole used a Medela pump for a year with both boys (so two years total) and it was still going strong.

Also, remember that no pump is going to be as effective at emptying your breasts as your baby, so leave a “margin for error”. The amount you’re able to pump out with a high-quality pump will be at least slightly less than your baby can draw out of your breasts. Finally, don’t be overly concerned if you’re not able to pump out much milk. This exercise isn’t meant to frighten or frustrate you!

What It Means If You Have “Large Cups”

If you are able to store 6 or more ounces in your “measuring cups,” then you can probably go 6-8 hours without affecting your milk supply. Most babies who are exclusively breastfeeding drink 25-35 ounces of milk per day. Moms who routinely store 6 or more ounces of milk in their breasts at one time may be able to feed their babies 5-6 times per day (although this also depends on the appetite of the baby.)

Remember too that some babies have reflux or small stomach capacities and cannot tolerate large amounts of milk. These babies will need to eat more often even if the moms can store a great deal of milk at one time.

What It Means If You Have “Small Cups”

Moms who store less than 6 ounces at a time (those who have smaller “measuring cups”) can still make plenty of milk, because overall milk production is not dependent on the size of the “measuring cups.” Your body can make plenty of milk as long as there is a place for the milk to go. Moms with smaller cups need to feed their babies more frequently to keep room in the storage space for more milk. So a mom who has a storage space of 3 ounces can still exclusively breastfeed; however, she will need to feed her baby 9-12 times per day for the entire time of exclusive breastfeeding. This is much different than a mom who can store 8 ounces and may need to feed her baby just 5 times per day. What’s important is for your baby to get the number of ounces he needs to thrive. It doesn’t matter so much if he gets that amount in 5 feedings or 10 feedings.

Remember, if you have concerns about your baby’s growth or the number of feedings he needs, contact his doctor or a lactation consultant who can evaluate your baby in person. Keep in mind, too, that a baby’s weight gain is the BEST indicator of adequate growth.

Additional Resources

For more information about breastfeeding and sleep training, take a look at these articles: