How does milk supply change over the course of lactation

Written by: Sabrina Granniss, IBCLC

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Time to read 8 min

Breast milk adapts and changes over time. A mother’s breasts change in how they feel during the first weeks of making milk versus a few months later in their feeding or pumping journey. The breastfeeding relationship changes as your baby grows from baby to toddler and older and looks a little different for each mom and baby. One thing does not change, and that is the continued benefits of breastfeeding for you and your baby.


Your milk supply begins well before you have your baby. Making milk is a complex process, beginning with mammary development when you are a fetus. While in utero, the mammary line forms a basic ductal system. 


Hormones during puberty influence the growth of the ductal system. As estrogen is released from the ovaries during puberty, breasts grow in size, and secretory glands form on milk ducts as the ductal system matures. The areola darkens, and the nipple may be more erect as the tissue stretches. 

Breast changes during pregnancy

  • Breasts grow in size. 
  • The areola becomes darker.
  • Bumps around the nipple on the areola called Montgomery glands may become more pronounced.
  • More veins on your chest become visible as your breasts prepare for milk production. 
  • If you do not experience changes to your breasts during pregnancy, consider a prenatal consultation with an International Board Certified Lactation Consultant (IBCLC) to assess other risk factors associated with low milk supply. 
  • For some people, it is normal to experience fewer changes to their breasts, and it doesn’t impact their ability to make milk for their baby.

Colostrum

You begin to produce colostrum as early as 12-16 weeks pregnant. When your baby is born, they will survive on this highly concentrated, nutrient-rich food for the first few days of life. Colostrum has laxative properties that help your baby pass meconium.  Meconium is thick and sticky. It is what is left in your baby’s intestines from them swallowing amniotic fluid in utero. The water parts of amniotic fluid are absorbed, and the rest is left lining the intestines. 


Colostrum is low in lactose and high in protein, beta-carotene, and immune factors. Oligosaccharides in breast milk are not digested by the baby as food but protect them from pathogens. They are carbohydrates that are food for the bacteria in your baby’s gut that help develop their immune system.


Colostrum may leak during pregnancy, but not always, and doesn’t determine or predict your milk supply. Keeping the baby skin-to-skin as often as possible helps with the establishment of the milk supply and stimulates milk production. Skin-to-skin contact regulates your baby’s temperature, heart rate, and breathing, and your baby will cry less. (1) Being skin-to-skin frequently in the first week after birth helps you and your baby begin to communicate and bond. As they cue and you respond, a dialogue begins. 


In the first three days postpartum, you will make between 1-2 oz of colostrum per day. On day one, your baby will take about ½ tsp. - 2 tsp of colostrum. (5) This amount increases on day 2 and day 3 to about ½ - 1 oz. 

Milk “comes in”

Milk volume increases as it changes from colostrum to transitional and mature milk. It is higher in lactose and carbohydrates than colostrum. (3) It is higher in fat to meet your baby’s needs as they grow so quickly. Milk volume begins to increase around days 2-5. The color of your milk will gradually change to a more white, creamy color compared to the rich yellow/orange color of colostrum. 


You may feel your breasts become heavier and full-feeling. You may leak milk. If you feel over-full or engorged, you will want to encourage your baby to nurse more often to help give you relief. If needed, cool compresses between feeding can reduce the swelling, while warm compresses just before feeding can help dilate the milk ducts and encourage milk flow. 

You may notice your baby’s feeding pattern begins to change with more milk volume. 

Your baby will increase how much milk they take over the first five weeks, typically drinking 1.5-3 oz per feeding. 

Your milk supply is being driven by your hormones and will be produced regardless of milk removal for the first few weeks postpartum, after which your baby’s demand for milk will dictate your milk supply. Skin-to-skin contact with your baby releases oxytocin, the love hormone, and signals the milk ejection reflex for milk to flow. The more often your baby nurses, the more times you are giving information to the body about how much milk is needed for your baby. 


It is important to watch your baby’s feeding cues. Begin feeding before they become hungry. Just like us, if we wait too long, we get a bit hangry, grab anything we can get our hands on, and maybe not eat as slowly, chewing our food well. 


When your baby is super hungry, it is harder for them to be calm, latch deeply, and feed well. The more often your baby nurses, the more often the breasts refill. Scheduling feeds have been shown to negatively affect milk supply by 3 -4 months postpartum and can be hard to recover. (6) 

Weeks 6 - 12

Your breasts may not feel the same as they used to. The always-full feeling decreases as prolactin levels decrease. Prolactin is released when milk is removed and signals to refill the tissue that holds and stores milk. So, the more often you feed your baby, the more often you signal to refill your storage areas with milk. When milk is not removed, a different hormone is released, signaling to slow down production, and less milk is made, lowering your supply. Breastfeeding supplements to increase milk supply can be a helpful tool but do not replace milk removal and the demand and supply production system.


Finding ways to get more nighttime sleep and go long stretches between having to nurse or pump can be tempting. Long periods between milk removals is not a great plan for most to maintain their milk supply. Prolactin has its own circadian rhythm. It is highest during the night. This remains true throughout the whole time you are lactating. (4) Removing milk when prolactin is naturally highest promotes milk regulation and adequate milk production.

Your baby drinks about  2 - 4 ounces each time they nurse. They will drink about 19-30 ounces per 24 hours, with the average being 24 ounces. (7)


From about one month old until 6 months old, your baby’s milk needs remain fairly constant.
 

6 months - 1 year postpartum

Solid foods begin to be introduced around the middle of the first year of your baby’s life. The introduction of solids is an exploration of texture, taste, and smell. They still rely on your milk to meet their needs. You will always nurse first and then give food. The more food your baby begins to eat over this period of time, the less milk they may take, and milk supply will decrease slightly. Until at least one year old, food remains complimentary to breast milk; it does not replace it.


As your baby gets older and explores their world more, they may nurse less often during the day or for shorter periods of time. Babies often make up for that time during the night. Middle-of-the-night feeds remain important for milk production and your baby’s weight gain.

 Babies take in about 30% of their calories from milk during the night.
 

Your baby is just beginning to realize they are independent from you, their own person. Breastfeeding offers emotional support and comfort. It gives them security as they learn so many new skills like crawling, standing, taking their first steps, and beginning to see the world in a new way.

Nursing past one year

Your milk benefits your child for as long as you breastfeed. Not all babies eat a lot of solid foods until closer to 18 months old. Continuing to give breast milk boosts their nutrition and immune system. If your baby catches a cold, sometimes the only thing they are willing to drink is your milk. It helps keep them fed and hydrated when they aren’t up for anything else.


Your milk supply will follow the demand of how often your child removes milk. Some children will begin to cut back on how often they nurse, while others nurse just as often as before. There is no one right way, and paying attention to your child’s unique needs is best.


Your older baby is more efficient at nursing than when they were only a few weeks or months old. Instead of taking 15-20 minutes to get the milk they need, now they come to you and may only need five minutes to get the amount of milk they need. 


Breast milk past one year postpartum is higher in fat and protein but lower in carbohydrates. (9) High IgA antibodies continue to fight off illness.

2-4 years postpartum and beyond

Breastfeeding until at least two years old is the recommendation of the World Health Organization and should continue for as long as mutually desired. 


Nursing during this stage looks completely different than when they were younger. They may nurse less often or for short snippets of time. They may not nurse at the same times each day, although nighttime and nap times still seem to be times they like the comfort and snuggles to relax and settle in.


Breastfeeding can make your growing child feel safe and meet their emotional needs. When they are learning yet more independence and interacting with other children, sometimes a nursing break gives them the reset they need to continue their play. A quick nurse in your lap stops crying and conflict as they learn to share toys and play with others. Dependence naturally forms independence. (8)  


The immune system is formed around age 3-4 years old. Continuing to give breast milk supports the healthy development of the immune system and gut health. This can mean less illness and better protection as they get older. 


Natural weaning happens when your child decides they no longer need to breastfeed. Anthropologists have looked at weaning through a lens of the child having gained four times their birth weight, tooth eruption, and the child’s age is at least six times the length of gestation. Natural weaning age spans a broad range, happening anytime between 2.5 to 7 years old. (10) 


As they grow, mature, and have their needs met, the need for breastfeeding falls into the background. While breastfeeding can seem like a 24-hour-a-day tiring job at the beginning of the journey, once your child is done and no longer breastfeeding, many mothers then feel like it all happened in the blink of an eye and cherish the snuggles, struggles, and successes of the breastfeeding relationship they had.


In summary, breast milk changes and adapts over time, and the breastfeeding relationship between a mother and her baby also changes. However, the benefits of breastfeeding continue to persist for both the mother and baby.

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