Your body truly is an amazing thing. Not only are you able to grow a baby inside your womb, but your body also makes the perfect food to feed it after birth: breast milk.
Breast milk is your body’s natural way of ensuring your baby has all the nutrients it needs. Even more amazing, your breasts are able to adjust your milk to fit your individual baby’s needs.
But how exactly does your body make breast milk?
While most are well aware that breast milk is made in the breasts, many women don’t know much more than that. However, understanding the process behind making breast milk can greatly help you during your breastfeeding journey.
The more you understand about breastfeeding, the easier it will ultimately be. So how exactly is breast milk made?

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How Breast Milk Is Made
Understanding how breast milk is produced is the first step to success in your breastfeeding journey. But did you know that your body starts preparing to breastfeed before your baby is even born?
Milk production starts during pregnancy
Among all the changes in your body that pregnancy brings, it also begins preparing to make milk for your baby. But your body doesn’t just get ready for breastfeeding. It may actually start producing breast milk before you baby is actually born.
In the third trimester, you may find that you leak some breast milk at times. This is a perfectly normal third trimester symptom, and is just a good sign that your body is ready to feed your newborn. Of course, not everyone leaks milk during their pregnancy, but that doesn’t mean your body is ready or able to breastfeed.
Before I go into that any more, let’s back up a minute and talk about exactly how your body prepares to breastfeed.
Hormones cause breasts to begin preparation
Like most other pregnancy related things, hormones are what signal your breasts to begin preparing to produce breast milk. This process starts early on in the first trimester, leading to swollen and tender breasts as uncomfortable first trimester symptoms.
Pre-pregnancy, your breast is made up primarily of fatty tissue. As hormones stimulate your breast to prepare for breastfeeding, your body will begin to build milk ducts and alveoli, or the milk sacks responsible for producing breast milk.
Will the size of your breast make a difference?
Ultimately, the amount of alveoli and milk ducts created during pregnancy will determine how much milk you are able to produce.
Surprisingly, breast size has nothing to do with it. Regardless of whether you have small breasts or larger breasts, the amount of milk sacs and ducks is what matters when it comes to milk production.
The more milk sacs, or alveoli, that your body builds during pregnancy, the more milk you will be capable of producing. Fewer sacs typically equals less milk being produced at one time.
Of course, even if you have fewer milk sacs and ducts, you can still successfully breastfeed. You may find that you simply need to feed baby more frequently, or stimulate your breasts more to encourage them to produce more milk.
Oversupply
While many wish for the ability to produce more milk, it’s not always a good thing. If you end up with too many milk sacs and ducts producing more than needed, you can end up with an oversupply. While an oversupply may sound like a good thing, it comes with it’s own set of potential problems.
An oversupply often comes with a greater risk of clogged ducts and mastitis, neither of which are good. Oversupplies may even out later on as your milk supply regulates around three months postpartum.
One great way to take advantage of an oversupply is to take the opportunity to build up a freezer stash, or donate extra milk to a milk bank.

Good signs your body is ready to breastfeed
While I was still in the hospital after delivering Elijah, I got the opportunity to work directly with a lactation consultant. It was definitely a huge help, and helped us adjust to our new breastfeeding journey.
While it was a little awkward at times (I’m typically on the more modest side…), I learned a lot from her that I don’t think I would have known otherwise.
One of the many things she taught me was some signs that my body had properly prepared for breastfeeding. While all these signs may not be present for everyone, here are some good indicators that your body is ready and able to produce breast milk.
Breasts get bigger
One of the many pregnancy symptoms you can expect is breast enlargement. Your breasts may go up a cup size as they prepare for breastfeeding. While this may be uncomfortable at times, it’s a good sign as far as breastfeeding goes.
Stretch marks
It’s not uncommon to develop stretch marks on your breasts during pregnancy. Stretch marks are the result of skin being expanded faster than it is able to stretch. Unfortunately, stretch marks are a common thing in pregnancy, especially in the third trimester.
Stretch marks on your breasts are the result of your breasts growing faster than your skin is able to stretch. But don’t let that affect how you feel about yourself. It’s actually a good sign that your body is preparing to make breast milk!
Larger areolas
The areola is the dark circle of skin surrounding your nipple. As your body prepares to produce milk, the areola often becomes larger.
While it’s a good indicator for breastfeeding, it’s definitely one of the many odd pregnancy changes to your body.
Leaking milk
It probably goes without saying that leaking milk during pregnancy is a great sign that your body is ready for your baby to breastfeed! Leaking milk shows that your body is already producing the first milk your baby will taste.
While it can be a pain to deal with the leaking at times, dealing with milk leakage is fairly simple. Simple stick some breast pads in your bra to soak up the leaking (I’m personally a fan of these reusable bamboo breast pads).
And if you’re really motivated, you can even hand express the milk. Be sure to properly store and freeze it to feed your baby after birth!
Types of Breast Milk Made
After your baby is born, a combination of hormones and nipple stimulation—most commonly from baby sucking—will signal your body to release milk into the milk ducts. From there, your baby will suck it out through your nipple in a process known as nursing.
But did you know that your body will make several different types of breast milk over the course of your breastfeeding journey?
Colostrum
The very first breast milk your baby will consume is known as colostrum. Colostrum is thicker than the mature milk your baby will drink later on, and has a more yellow color.
This first milk is packed with antibodies and crucial nutrients that your baby will need. Although colostrum is only produced for the first few days after birth, it is a super food that contains everything that your baby needs in the first few days of life.
Even though colostrum is the only food your baby needs for those first few days, it is only produced in surprisingly small quantities. However, don’t let that worry you. Your baby’s stomach is extremely small, and will grow quite a bit during the first few days after birth.
Transitional Milk
After a few days, your body will produce transitional milk, which is basically just a combination of colostrum and mature milk. As mature milk begins to be made, it will mix with colostrum until it is the only type of milk being produced.
Transitional milk is just what it sounds like—a transition. You can expect this type of milk to be thinner than colostrum, though not as thin as mature milk. It will also have whiter color, though it may still be more yellow than your mature milk will be.
Mature Milk
Within about two weeks, transitional milk will turn into mature breast milk. Mature milk is what your baby will drink until weaned.
Despite the fact that your baby may be drinking mature milk for a year or more, your baby will always have the exact nutrients needed. Mature breast milk will change in composition to provide all the antibodies and nutrients needed at any given time.
Your body is able to adapt your milk to your baby’s needs. When your baby nurses, your body is able to decipher what is needed from you baby’s saliva. It sounds kinda gross, but it’s also kinda cool, too. From your baby’s saliva, your body can adjust what’s in your breast milk to suit your individual baby’s needs.
Not only is your mature breast milk able to adjust to your baby’s needs, it also is made in two different types.

Foremilk
Foremilk is the first milk that is released from your breast for your baby to drink. The foremilk is where the majority of the nutrients and antibodies are found. It also tends to be a bit thinner, although you may not notice the difference.
Hindmilk
Hindmilk is the second “wave” of milk that is released when nursing. It is primarily fatty milk, which contains the bulk of the fat and calories that your baby needs to grow.
In order to ensure your baby gets enough hindmilk, it’s important to make sure your baby completely empties your breast before offering the other side. Not enough hindmilk can lead problems such as inadequate weight gain.
How does your body know how much breast milk to make?
It’s incredible that your body knows how to adapt your milk to provide the right antibodies and nutrients, as well as the right amount of foremilk and hindmilk. But that’s not the only ways your body adjusts to your baby’s needs.
You’re amazing body also knows how to adjust how much milk it produces to provide the amount your baby needs. At around three months postpartum, your milk supply regulates to only produce as much as your baby needs.
Rule of Supply And Demand
How much milk your breasts make depends upon the rule of supply and demand. In short, your breasts will only make as much milk as is being taken from them.
In the beginning of your breastfeeding journey, you will likely have more milk than necessary. This often leads to engorgement, which is common after your mature milk comes in.
As your baby nurses, your body will adjust to only produce as much milk as is being removed. Your milk supply will regulate to meet the demand.
Early on, the demand will not be as great. But as your baby grows, your milk supply will increase as your baby drinks more during a nursing session.
Cluster feeding, or nursing multiple times in a short time span, alerts your body that your baby needs more milk. While often inconvenient, it’s important to not ignore cluster feeding, as it will trigger your breasts to increase your milk supply.
Emptying of the Breasts
The key to breast milk supply is in the emptying of the breasts. When your baby completely empties the breast of milk, it will signal your body to make more to meet the need.
That’s why it’s especially important to empty each breast if you have a low milk supply and are trying to increase your supply.
Likewise, when you are ready to wean your baby, dropping feeds and nursing less frequently will signal your body to begin drying up your milk.
If your breasts are not being emptied, they may begin to produce less. So if you’re not intentionally weaning, be sure to have your baby completely empty each breast to maintain your supply.
Did you know these facts about breastfeeding?
Your body is so amazing! It is designed to provide for your individual baby, and adjust your breast milk as needed.
Did you know how your body makes breast milk? How is your breastfeeding journey going?
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