Breastfeeding: One breast produces more milk than the other
- Elise Armoiry My Baby Moon
- Jan 15
- 4 min read
Is it normal for one breast to produce more milk than the other?
Breastfeeding can often be sprinkled with doubts and questions. One of the most frequent questions I hear in consultation as an IBCLC Lactation Consultant is that of the difference in production between the two breasts.
If you are wondering why one breast seems fuller, faster, or simply produces more milk than the other, know this: you are not alone! The short answer is: Yes, it is completely normal.
Here are some explanations to reassure you and, if necessary, help you explore solutions.
If you are looking for clear and evidence-based information on breastfeeding,you can book an online consultation
Why don't my two breasts produce the same amount of milk?
It is rare for a person to produce exactly the same amount of breast milk on both sides. Riordan et al indicate that the right breast often produces more than the left breast; it is assumed that this is due to the position or the greater blood circulation in that breast. Large variations in production are described between the two breasts in the literature, such as, for example, a woman having a storage capacity of 600 ml in one breast and 190 ml in the other.
Several factors, most often harmless, can explain this production asymmetry:
Anatomical and physiological differences: As with any pair of organs (feet, hands), there are natural variations in the density of glandular tissue and the storage capacity of each breast. One breast may simply have more mammary gland than the other. 88% of women have a natural asymmetry between the breasts (Lorraine Kit Ying Ho et al).
Baby's "preferred" breast: Babies often develop a preference for one side, sometimes related to how they are held, the ease of obtaining milk, or even the position of your arm. If one breast is sucked more often, it is more stimulated and therefore naturally produces more milk, in accordance with the principle of supply and demand. The Gestalt position, which I propose in consultation, helps reduce the risk of preference for one breast by restoring an optimal position on both sides.
Breastfeeding history: A past case of mastitis, breast surgery (even cosmetic), or a history of nipple injuries on one side may have had an impact on the production capacity of that breast.
Rare conditions (but to be ruled out): Rarer conditions such as breast hypoplasia (insufficient development of glandular tissue) can explain a very significant difference in size and production between the two breasts (Kam et al). In case of doubt, a Lactation Consultant can evaluate your situation.
Should I worry about this production asymmetry?
In the vast majority of cases, no.
What matters is not the amount produced by each individual breast, but the total amount of milk your baby receives over 24 hours. If your baby wets enough diapers, gains weight appropriately, and looks satisfied after feedings, the difference in production is a mere curiosity and not a feeding problem.
When to seek help?
You should consult if:
The difference is so marked that it causes a major breastfeeding difficulty (your baby systematically refuses the "weak" breast).
You notice insufficient weight gain in your baby.
You have pain, frequent engorgement, or the difference in size causes you significant physical or emotional discomfort.
How to try to balance production between the two breasts?
If you actively wish to try to increase production on the "weak" side, here are some strategies based on the principle of supply and demand:
Start the feeding on the "weak" side: Your baby is the most motivated and sucks most efficiently at the beginning of the feeding. Putting them first on the breast that needs to be stimulated can help increase its production.
Double pumping: Pumping your milk from both sides at the same time stimulates total milk production and increases feeding efficiency. Pumping the weak breast after a feeding can also send a strong signal to increase the supply.
Massage and Compression: Massaging and compressing the "weak" breast during the feeding or expression could help empty the breast more effectively, which is a powerful signal for the body to produce more milk; however, this technique is controversial (risk of mastitis).
Need a personalized plan to optimize your lactation?
For complete, personalized, and caring support, you can contact me: Élise Armoiry of My Baby Moon.
As an experienced lactation consultant, I specialize in helping mothers with all challenges related to milk production, whether it is low production, marked asymmetry, or overproduction. Online support is often the best way to get professional, fast support adapted to your daily life.
You can contact me for advice or questions: "My Baby Moon" by Elise Armoiry, IBCLC lactation consultant & founder of My Baby Moon. Over 2000 families supported since 2014. Doctor of Pharmacy by training, specialized in breastfeeding and sleep, trained with Dr. Pam Douglas.
Email: info@mybabymoonibclc.com Tel: 07.49.50.67.82 Website: https://www.mybabymoonibclc.com/
Bibliographic References
Ho LKY, Jafari S, Crittenden T, van Essen P, Smallman A, Dean NR. A qualitative study on the experiences of women undergoing surgery for developmental breast asymmetry. Womens Health (Lond). 2024 Jan-Dec;20:17455057241274901. doi: 10.1177/17455057241274901. PMID: 39238214; PMCID: PMC11378208.
Kam RL, Amir LH, Cullinane M, Ingram J, Li X, Nommsen-Rivers LA. Breast hypoplasia markers among women who report insufficient milk production: A retrospective online survey. PLoS One. 2024 Feb 29;19(2):e0299642. doi: 10.1371/journal.pone.0299642. PMID: 38421972; PMCID: PMC10903845.
Riordan et al. Breastfeeding and Human Lactation, 5th edition; 2016.
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