One Breast Producing Less Milk Than The Other? Mine, Too!

Breastfeeding is one of the most natural and beneficial ways to feed a baby. It provides perfect nutrition for infants and has numerous benefits for both mom and baby. It also comes with some challenges. Some moms may experience a common issue of one breast producing less milk than the other when breastfeeding or pumping breast milk. This can lead to confusion and frustration, but it’s totally and completely normal. I’ve breastfed three babies and for all three babies my “slacker boob” has produced less milk than the other. If you’re experiencing this, too, read on to find out why.

Why One Breast Produces Less Milk

There are several reasons why one breast may produce less milk than the other when breastfeeding or pumping. Here are the most common reasons:

Breast Anatomy & Size – #1 Reason One Breast Produces Less Milk Than the Other

Breast anatomy can play a role in milk production. According to the University of Utah, 90% of women have one breast that is larger than the other. If you have a noticeable difference in the size of your breasts, it could be the cause of one breast producing less milk than the other. If you pump breast milk, make sure that you have the correct pump flange size for both of your breasts. One breast may be a different size than the other. Check out our guide on Determining Your Correct Flange Size (So Pumping Doesn’t Hurt!) for more help.

Related article: Does Flange Size Affect Milk Output? Yes, Here’s How.

Additionally, one breast may produce less milk than the other due to disparity in glandular tissue. Glandular tissue refers to the milk-producing tissue in the breast, which is made up of milk ducts, lobes, and alveoli. The alveoli are small sacs within the lobes that produce and store milk. The more glandular tissue a woman has in her breast, the more milk she is likely to produce.

During pregnancy, hormonal changes cause the glandular tissue in the breast to develop and prepare for lactation. After giving birth, the baby’s suckling stimulates the release of hormones like prolactin and oxytocin, which trigger milk production and letdown. The more glandular tissue a woman has, the more efficiently these hormones are produced, and the more milk she can produce. It’s important to keep in mind that breast size doesn’t necessarily determine the amount of glandular tissue a woman has.

Related article: The 5 Best Nursing Bras According to Breastfeeding Moms

It’s hard to determine the amount of glandular tissue you have without breast imaging, but you can get a pretty good idea yourself by using our breast milk storage capacity chart below. Note that one breast may have more glandular tissues and, thus, a higher breast milk storage capacity than the other. This could be why one breast produces less milk than the other.

pros and cons of power pumping, one breast producing less milk than the other

Breastfeeding Position and Frequency (+ Pumping)

The position in which the baby is held during breastfeeding can affect milk production. If the baby is consistently latching onto one breast more than the other, it can result in the other breast producing less milk. Additionally, breastfeeding frequency plays a significant role in milk production. If a baby consistently nurses on that same breast, it will stimulate more milk production in that breast. This can result in less milk production in the other breast if the baby is not nursing on it as frequently. If your baby prefers a certain breast over the other, try to encourage baby to nurse on the other side by switching to different breastfeeding holds.

If you pump breast milk reguarly, try pumping on your slacker boob longer than on the breast that produces more milk. This will signal your body to produce more milk in that breast, thus increasing your milk supply. You can also try pumping breast milk on your lower output breast for 10 minutes after a nursing session.

Related article: Accidentally Went 6 Hours Without Breastfeeding? Don’t Panic!


Stress can affect milk production by interfering with the release of hormones responsible for milk production. If you are experiencing stress or anxiety, you may find that one breast produces less milk than the other. It’s often laughable to think about controlling your stress level when you have an infant who isn’t sleeping, but try your best to find ways to relax–especially when it’s time to breastfeed or pump. This could involve looking at your baby or pictures of your baby, listening to relaxing music, or simply laying back and resting for the few minutes your baby (or pump) is nursing.

Check out #9 on our list of How to Increase Breast Milk Supply (FAST) to read about using meditation to increase breast milk supply. There’s actually scientific evidence to back it up!

Related article: Breastfeeding While Sick: Everything You Need to Know

Breast Complications

Certain breastfeeding complications such as mastitis, clogged ducts, or nipple trauma can also affect milk production in one breast. These issues can cause inflammation or pain, which can decrease milk production in the affected breast. If you’re dealing with repeated clogged milk ducts in one of your breasts or are finding breastfeeding painful, we have several articles that you may find helpful:

Certain factors such as prior breast surgery, hormonal imbalances, or medical conditions can also be the reason one breast is producing less milk than the other. In these cases, you may need to seek professional help from a lactation consultant or your healthcare provider to identify and manage the underlying cause.

How to Manage One Breast Producing Less Milk

If you notice that one breast is producing less milk than the other, there are several things you can try to manage the issue. Here are some tips:

Frequent Breastfeeding

Frequent breastfeeding can help increase milk production in the affected breast. The baby should be encouraged to nurse on the affected breast as often as possible. Try starting your baby on the breast producing less milk at each breastfeeding session. As we mentioned previously, you can also try different breastfeeding positions (laid back, football hold, cross cradle hold, side lying, cradle hold, etc.).

Related article: 10 Reasons For A Sudden Drop in Milk Supply (and What To Do About It!)

Breast Compression

Breast compression can help increase milk flow and stimulate milk production. Trying using your hands to compress the breast gently while the baby is nursing. Try also pressing on the top (toward your chest) and sides (under your armpit) of your breast to encourage milk flow. Make sure to always press towards your nipple to express milk out.

Related article: Breasts Not Responding to Pump Anymore? Try This.


As mentioned previously, pumping the affected breast after breastfeeding can help stimulate milk production. You can also try pumping the affected breast in between feedings for 10-15 minutes to increase milk production. An additional option is to try power pumping on the breast producing less milk by using the below schedule. See our article on the Pros and Cons of Power Pumping for more information.

Pros and cons of power pumping. One breast producing less milk.

Related article: Breast Pump Not Working? Here’s 5 Troubleshooting Tips to Try.

Seek Professional Help

Having one breast producing more milk than the other is totally normal and incredibly common. However, if this issue is causing significant concern, seek help from a lactation consultant or your healthcare provider. They can help identify the underlying cause and provide recommendations for managing the issue.

One breast producing less milk than the other is something many breastfeeding moms face. The reasons for this issue can vary, but there are several things to try if it’s causing concern. Frequent breastfeeding, breast compression, pumping, and switching sides during breastfeeding are all effective ways to increase milk production in your slacker boob. Again, I’ve breastfed three babies with a left side slacker boob and it’s never caused any major issues. I hope it doesn’t for you either!

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Shannon founded Work Breastfeed Mom in 2019 during her second round of pumping at work. She was tired of googling the same pumping questions over and over again, and discouraged at the lack of websites aimed at working breastfeeding moms. So, she created one herself. Shannon lives, works, and doles out Puffs to her little people in sunny Florida. She has her MBA and works as a strategic planner for a large healthcare system. She is passionate about coffee, memoirs, paddle boarding, and skincare routines. Shannon is mom to Scarlett and Ivy, and hopes to have more babies if her career allows.