How to Balance Uneven Breasts When You Are Breastfeeding

Mother breastfeeding son while sitting by window at home
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If you're breastfeeding, you will experience some degree of unevenness in your breasts at some point. Depending on which breast you last nursed on and whether you breastfeed from one side or both sides at each feeding, your breasts will fill up with breast milk at different rates.

This unevenness is normal, and it's usually more noticeable during the first few weeks after the birth of your baby when your milk supply is still adjusting. However, even after the first few weeks, your breasts can still become lopsided.

Why Breasts May Become Uneven

If one breast gets more stimulation than the other, it will produce more milk and grow larger than the other one. It can happen when a baby prefers one breast over the other or if you start nursing on the same breast most of the time.

As long as your child is getting enough breast milk and growing at a steady rate, uneven breasts aren't really anything to worry about. But, if you're uncomfortable or it bothers you, there are some things you can do to try to get your breasts back to a similar size.

How to Even Out Your Breasts

Start every feeding on the smaller breast until that side catches up in size. After a few days, the smaller breast should begin to make more breast milk, and you should notice your breasts becoming more balanced. After you breastfeed your baby, you can use a breast pump to stimulate your smaller breast further. Pumping can increase the breast milk supply which should help to increase the size of the breast.

If your baby has a breast preference and refuses to nurse on one side, try to find out the reason behind your child's preference. Do not completely neglect the larger breast or it could end up becoming the smaller one, and you will be right back where you started. Keep the milk supply up in your larger breast by pumping the milk in that breast while you're spending more time breastfeeding on the other one.

While you're breastfeeding more often on the smaller breast, your larger breast may become overfull with breast milk. You can pump or ​hand express a little of your breast milk from that breast to relieve the pain and pressure and avoid the complications of ​​breast engorgement. You can collect and store that breastmilk to use at a later time.

Once your breasts are back to where you'd like them to be, go back to alternating the breast you start each feeding on to help keep them even.

Breastfeeding From Only One Side

If you breastfeed from only one breast at each feeding, your breasts will probably be uneven. The breast that you just breastfed on will be smaller, and the other side will be filling up with breast milk for the next feeding. Then after the next feeding, it will be the opposite.

As long as you don't mind, it's not a problem at all. However, if you would rather your breasts stay more even from feeding to feeding, you can breastfeed from both breasts at each feeding to keep them more balanced.

When Are Uneven Breasts a Concern?

For most breastfeeding moms, uneven breasts are not a medical concern. But, if one breast has been consistently smaller from the beginning and did not get any larger throughout your pregnancy or the early postpartum period, talk to your doctor.

Although it is not a common problem, a small percentage of women have hypoplastic breasts which could affect just one side. If this is the case, you may not be able to even out your breasts, but you can still breastfeed. 

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  1. Arbour MW, Kessler JL. Mammary hypoplasia: not every breast can produce sufficient milk. J Midwifery Womens Health. 2013;58(4):457-461. doi:10.1111/jmwh.12070

Additional Reading
  • American Academy of Pediatrics. New Mother’s Guide to Breastfeeding. Bantam Books, 2011.

  • Lawrence RA, Lawrence RM. Breastfeeding A Guide for the Medical Profession, Eighth Edition. Elsevier Health Sciences, 2015.