One Breast Produces More Milk Than Other: Reasons And Tips

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You may be concerned that one breast produces more milk than the other. It is normal for this to happen as the milk flow in one breast could be faster. You may have an uneven milk supply after starting expressing milk or breastfeeding. Babies may also prefer feeding from the breast that produces more milk (1).

Most mothers, due to this, may prefer one-sided feeding. This may cause the more milk-producing breast to produce in excess while the other breast may show a decline in milk production. Note that it is important that a baby is fed from both breasts for the sake of optimum milk production. Hence, we have included tips to improve uneven milk supply in this post.

Causes Of Uneven Milk Supply In The Breasts

Uneven milk supply or less milk supply in one breast than the other is common and normal in most cases. There is nothing to be concerned about if both the nursing mom and the baby are comfortable.

The following factors may lead to uneven milk supply in some breastfeeding women (1).

  • Baby’s preferences: Some babies may prefer to latch and feed on one breast than the other. This may cause more milk supply in the preferred breast than the other one. Physical discomfort from birth injuries, nasal congestion, and ear infections may make babies prefer certain nursing positions, causing them to choose one breast over the other. Some babies may feed on one side after vaccinations for a few days; this can be due to pain at the injection site. The size and shape of the nipple (inverted or flat nipple) may vary in some cases, and the baby may tend to feed from the breast where they can latch easily.
  • Nursing mom’s preferences: Some mothers may unknowingly prefer feeding from one breast more often or more time than the other side. This can be due to comfortable feeding positions or other reasons. One-sided breastfeeding may make your breasts look lopsided due to uneven milk production.
  • Insufficient glandular tissue: The amount of glandular tissue (milk-making tissues) and the milk ducts or lactiferous duct (tubes that carry milk from the glandular tissue) may vary in each breast. Most women may have asymmetrical breast size and shape due to various factors, including fat deposits. Uneven breast size due to fat deposits may not impact the amount of milk supply.
  • Letdown differences: Less forceful letdown can also be associated with less milk supply in one breast. The letdown reflex causes breast milk flow. When the baby sucks, nerves are stimulated, leading to the release of prolactin and oxytocin hormones that help in milk production and flow(2).
  • Breast trauma and breast surgeries: Milk supply can be affected by injury and surgery of the breast tissue. This can be due to damage or removal of milk-producing tissues.

Babies may often demand more feeding when they are fed from the less-producing breast. It is always recommended to look for the reasons and make necessary nursing changes to overcome this issue. Seeking help from a certified lactation consultant can be beneficial.

Does Unequal Milk Production Affect The Baby?

Many nursing mothers can adequately feed their babies from one side alone. Uneven milk supply may not affect the baby’s nutritional needs since they can be fed from both breasts, and milk production increases with increasing demand. Frequent feeding may help the baby to get adequate nutrition in such cases.

You can check for signs that indicate the baby is well-fed, such as weight gain, adequate soiled diapers per day, good activeness, and timely achievement of developmental milestones (3). You may seek help from a lactation professional if there is a concern.

Tips To Achieve Equal Milk Production In Both Breasts

 Uneven milk supply due to fewer milk-making tissues cannot be changed. Changing mom’s and baby’s preferences may help to maintain a good milk supply in both breasts. The following tips may help to enhance and even milk supply in both breasts.

  • Always begin to feed on the slow side: Babies vigorously begin to feed when they are hungry, and their sucking reflex may help enhance the milk supply in the less milk-producing breast. Feeding the slow side and shifting to the other side can help moms to maintain even milk supply.
  • Nurse or pump more frequently from the low-producing side: Frequent removal of milk helps to enhance milk production. The sucking reflex stimulates more milk production in the low-producing breast. However, never neglect to feed on the high-producing breast since this may lead to engorgement.
  • Avoid one-sided breastfeeding: Feeding on both breasts from the initial days of breastfeeding can help to avoid uneven milk production. Try beginning to feed on alternate breasts on each feeding section. One-sided breastfeeding is usually recommended for moms who have any conditions preventing milk supply from the other breast.
  • Try massage with hands: Massaging the low-producing breast with hands may enhance milk flow. You may do massages from the base towards the nipple.
  • Express milk: You may use breast pumps to express milk from the less productive breast after a feeding session to increase milk production. Milk supply is directly related to the demand, so pumps can be helpful in case the baby refuses to feed on one side.
  • Change baby’s preferences: Encourage your baby to feed on the less preferred side by changing nursing positions. Try to feed on the less preferred side when they are too hungry or tired to avoid refusals. Identifying and managing physical discomforts may help to reduce your baby’s aversion towards one breast.

These tips can help breastfeeding moms enhance milk supply in both breasts and often avoid lopsidedness. In most cases, lopsidedness (uneven breasts) improves when the baby starts to wean on solids.

Frequently Asked Questions

1. Is it possible for one breast to dry up?

Several reasons are responsible for uneven milk production in the breasts during breastfeeding. Hence, it might be possible that one breast has little to no milk production while your baby gets milk from the other breast. In such cases, the former breast might be considered to have ‘dried up.’ But eventually, the milk flow will return to normal in both the breasts.

2. Why does one breast fill faster than the other?

A common reason for one breast filling up faster than the other might be that your baby prefers one breast more. Therefore, their suckling action and the let-down of milk from the breast trigger its reflex and cause it to fill up faster than the other breast.

It is common to notice that one breast produces more milk than the other. One-sided feeding, insufficient letdown, and other medical conditions could lead to uneven milk supply in the breasts. However, this is not a serious concern as long as your infant is active, well-fed, gains appropriate weight, and soils a sufficient number of diapers. Meanwhile, you may try measures such as initiating feeding and pumping milk from the low-producing breast, massaging, and expressing milk to enhance milk supply. Furthermore, you may consult a lactation professional to learn more about the right position and techniques to facilitate consistent breastfeeding.

Key Pointers

  • Insufficient glandular tissue, breast trauma, and breast surgeries are a few causes of unequal milk supply in breasts.
  • Begin feeding on the side where the milk supply is low as hungry babies tend to suck vigorously initially.
  • Massage from the base towards the nipple, using an electric or manual breast pump are some effective ways to increase milk production.


MomJunction's articles are written after analyzing the research works of expert authors and institutions. Our references consist of resources established by authorities in their respective fields. You can learn more about the authenticity of the information we present in our editorial policy.
1. One Sided Breastfeeding; Australian Breastfeeding Association
2. The Physiological Basis of Breastfeeding; US National Library of Medicine
3. How Can I Tell If My Baby Is Getting Enough Milk?; La Leche League International
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Dr Bisny T. Joseph

Dr. Bisny T. Joseph is a Georgian Board-certified physician. She has completed her professional graduate degree as a medical doctor from Tbilisi State Medical University, Georgia. She has 3+ years of experience in various sectors of medical affairs as a physician, medical reviewer, medical writer, health coach, and Q&A expert. Her interest in digital medical education and patient education made... more

Mindy Cockeram

Mindy Cockeram is a Childbirth and Breastfeeding Educator currently residing in Southern California, where she teaches at a non-profit hospital. Her career began after the birth of her second child when she changed career direction and trained as an antenatal teacher with the National Childbirth Trust in London, England. She taught childbirth classes for both the Wimbledon & Wandsworth Branch... more