Breasts come in different shapes and sizes. Some people believe larger sized breasts will produce more breastmilk and smaller breasts will produce less breastmilk, but these beliefs are actually not true! Let’s dive in and explore what actually matters when it comes to your milk storage capacity and how your milk storage capacity can impact your breastfeeding journey.
If breast size doesn’t matter, what does?
Inside your breasts, you have lobes that span out like flower petals from a flower. Housed inside these lobes are lobules and tiny bulbs that produce milk. These structures are linked through an interconnected web of tiny tubes called milk ducts. These milk ducts eventually transport milk from the lobes to the areola and pores on the nipple to feed your baby. Fat fills the rest of the space in the breast along with ligaments, blood vessels, and lymph vessels.
Oftentimes, differences in breast size are related to the amount of fat in the breast. This means the outer size of the breast is not an indicator of breastmilk production or milk storage capacity. The foundation of your milk supply is actually related to the amount of fully developed lobes, or milk making tissue, in your breast. For example, large breasts can have more fat and less milk making tissue resulting in a smaller milk storage capacity.
What is milk storage capacity?
Milk storage capacity refers to the amount of milk your breasts can physically hold at their fullest. Research has shown this volume varies widely from person to person and can range anywhere from 2.5 oz to 12.7 oz with the average being around 6 oz. This is the amount of milk available to your baby through direct nursing or pumping. Once that milk is removed from the breasts, your breastmilk will begin to refill.
The amount of milk in your breasts can also vary from day to day and time of day. For example, most people experience the largest milk output in the early hours of the morning when prolactin (milk producing hormone) levels are the highest and lower milk output in the evening when prolactin levels are the lowest. This likely explains why babies cluster feed, or feed more frequently, in the evening.
Will I have a low milk supply if I have a small storage capacity?
Chronic low milk supply affects up to 15% of people and means you are able to produce milk, but not enough to exclusively breastfeed your baby to meet their nutritional needs. If you believe you do have a low milk supply, check out What Your Lactation Consultant Wants You to Know About Low Milk Supply.
Having a small storage capacity is different because it does not equate to overall milk supply. If you have a smaller storage capacity, this means you will be feeding or pumping more frequently than those with a larger storage capacity to meet your baby’s nutritional needs. For example, if your storage capacity is 2.5-3 oz, your baby may demand to eat closer to every 2 hours. As long as your baby is gaining weight and growing well and your feeding routine is working for you, there is no need to change anything!
Kelly Bonyata of kellymom.com illustrates this concept brilliantly! She says: think of storage capacity as a cup – you can easily drink a large amount of water throughout the day using any size of cup – small, medium or large – but if you use a smaller cup it will be refilled more often.
Finding Your Magic Number
One lactation consultant, Nancy Mohrbacher, describes finding your Magic Number, or the number of times someone needs to pump or nurse in a 24 hour period to maintain their milk supply. To find this number, take the average number of nursing sessions in a 24 hour period when: 1) you and your baby are home together, 2) they are older than 6 weeks, 3) you are feeding them on demand, and 4) they are gaining weight and growing well exclusively breastfeeding.
If you have a smaller milk storage capacity, you may find your magic number is 9-10 in order to maintain your supply. If you have a larger milk storage capacity, your magic number may be closer to 4 or 5. If your total number of daily breast emptyings goes below your magic number, you will likely see a decrease in your overall milk output.
Finding your magic number can be helpful if you are considering sleep training or returning back to work. If your goal is to maintain your milk supply, you will want to adjust your pumping or nursing schedule to make sure you are hitting your magic number each day. If you are dropping pumping or nursing sessions, your milk supply will down regulate over time.
Final Thoughts
Breasts truly are as unique as we are, and come in all shapes and sizes. While some may think that larger breasts mean more milk and smaller breasts mean less, these beliefs simply don't hold true. What really matters for milk storage capacity is the development of milk making tissue in the breast—not their outer appearance.
Your milk storage capacity, which varies widely among individuals, determines how much milk your breasts can hold at their fullest. This capacity isn't fixed; it changes throughout the day and can even change from one day to the next. Whether your capacity is on the higher end or more modest, it doesn't dictate your ability to breastfeed successfully. It just means you may need to nurse or pump more frequently to keep up with your baby's needs.
Remember, the key to a successful breastfeeding journey isn't breast size—it's understanding your body and your baby’s unique rhythm and needs. Embrace the magic of your milk-making capabilities, and know that you're doing an incredible job nurturing your little one, no matter what. Here's to celebrating every breastfeeding moment, big or small!
Sources:
Bonyata K. (2018, March 8). How Does Milk Production Work?
Mohrbacher, N. (2010, August 10). The Magic Number’ and Long-Term Milk Production (Parts I and II).
This site is intended for informational purposes only and does not provide medical advice. Please consult your physician or other health-care professional.
