If you’ve been breastfeeding or pumping for a while, you may have noticed that one breast produces more milk than the other. Don’t worry—you’re not alone! This is common, and it doesn’t mean you’re doing anything wrong. In this guide, we’ll explain why this happens and share simple tips to help balance things out.^1,2,3,4 With a little patience, you can encourage both breasts to work more evenly and ensure a steady milk supply for your baby.

Why You Might Have a Slacker Boob

There are many reasons why one breast might produce more (or less) milk than the other. In most cases, it’s completely normal and won’t affect your baby’s ability to get enough milk. Some common reasons include:^1,2,3,4 

• Baby’s Preference: If your baby prefers one breast over the other, the favored side will naturally produce more milk due to increased demand.
• Uneven Feeding: Consistently offering one side more often can lead to an imbalance in production. 
• Differences in Letdown: A stronger or faster letdown on one side might cause your baby to prefer the opposite breast, leading to an uneven supply.
• Milk-Making Tissue: Some women have more glandular tissue or milk ducts in one breast, which can naturally lead to higher milk production.
• Breast Development: Slight asymmetry is normal, but significant differences in size or development (even from puberty) may contribute to variations in milk output.
• Previous Breast Trauma: Any previous breast surgery, trauma, or medical procedures could impact milk supply on the affected side.

How to Encourage More Milk Production on the Slacker Side

If your baby is feeding well and gaining weight, there’s no need to worry about a slightly lower-producing breast. However, if you’d like to balance your supply, here are some effective strategies:^1,2,3,4

• Start Feedings on the Less-Productive Side: Babies tend to nurse more vigorously at the start of a feeding, which can help stimulate production.
• Offer More Frequent Feedings on the Slacker Side: Try the “three-breast method”—start with the lower-producing side, switch to the other, and then return to the first breast again to encourage more milk removal.
• Breast Massage and Compression: Gently massaging your breast while nursing or pumping can help stimulate more milk flow.
• Pump After Feedings: Pumping the slacker side for an extra 5-10 minutes after nursing signals your body to produce more milk.
• Extend Pumping Time: If pumping both breasts, try adding an extra 5-10 minutes on the slacker side for additional stimulation.
• Stay Hydrated and Eat Well: Drinking enough water and maintaining a nutrient-rich diet supports overall milk production.

What If You Have Noticeable Lopsidedness?

If the imbalance in milk production causes noticeable asymmetry, you’re not alone. Some mothers use a breast pad or extra layers in their bra for a more even appearance. Typically, any lopsidedness resolves after weaning or as your milk supply naturally evens out. However, if the difference is significant or persistent, consider reaching out to a Lactation Consultant  for personalized guidance.

What If I Have Questions?

If you are interested in learning more, these Aeroflow classes expand on some of the topics discussed above:

• Ultimate Breastfeeding Prep
• Pumping 101
• Lactation Q & A

Want More Info?

For a directory of Aeroflow’s other Care Guides offering information on pregnancy, baby care, and more, browse our comprehensive list of titles:

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