The Mature Breast Milk Stage

Color, Composition, and Changes in Breast Milk

Mother smiling while breastfeeding her baby

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Breast milk goes through changes from the end of pregnancy through the first few weeks after your baby is born. These changes are often called stages or phases. Colostrum is the first stage, transitional milk is the second stage, and mature breast milk is the final stage.

It is the mature breast milk that will adjust to meet your baby's changing needs throughout your breastfeeding journey. Here is what you need to know about mature breast milk including when you will make it, what it looks like, and how much you make.

When Mature Breast Milk Comes In

Breast milk starts out as colostrum. Then, in the first few days after your baby is born, it will begin to change, or transition, over to mature milk. As your mature milk starts to come in, it mixes with the colostrum.

During this mixing or transitional milk phase, you may feel your breasts getting larger and heavier as they fill up with breast milk. Many people experience breast engorgement during this time. It may be uncomfortable or even painful, but it should not last longer than a few days.

By the time you have been breastfeeding for 10 to 15 days, your breast milk will start to become mature milk.

What Mature Breast Milk Looks Like

Mature breast milk is usually white, light yellow, or blue-tinged, although it can occasionally appear as other colors depending on your diet and the colors of the foods that you eat. Blood from inside the milk ducts or from sore, cracked nipples can also make its way into your breast milk. If that happens, your breast milk may look pink, brown, or streaked with red.

Mature milk may look thin and similar to skim milk, or it may appear creamier. Frozen breast milk often appears yellow. Since it separates during freezing it may look layered, as well.

How Much Mature Milk You Will Make

Once your breast milk has transitioned into mature milk and fully comes in, the amount that you make will adjust according to your breastfeeding habits and your baby's needs. The more you breastfeed and pump your breast milk, the more mature milk you will make.

You will also produce more mature milk if you're breastfeeding twins or tandem nursing. However, if you are combining breastfeeding and formula feeding (and you aren't pumping to keep up your milk supply), you will make less milk.

The amount of mature breast milk that you make also changes as your baby grows. When your baby is one month old, they may be taking two to three ounces of breast milk at each feeding. So, you will be making approximately 24 ounces of breast milk each day.

This amount will go up as your baby gets bigger and takes more breast milk at each feeding. If you're breastfeeding exclusively, by the time your baby is six months old, you will be making between 36 and 48 ounces per day to meet their nutritional needs. Of course, this is just an estimate. Some people make less breast milk, and some people make much more.

Composition of Mature Breast Milk

We actually do not know everything that's in breast milk. However, scientists have so far identified over 200 different components that make up breast milk. Mature milk is full of nutrients such as carbohydrates, protein, fats, vitamins, and minerals. It contains everything your baby needs for healthy growth and development.

In addition to nutrients, breast milk contains antibodies that support your baby's immune system and help protect them from illness and disease.

How Mature Milk Changes

Once your breast milk reaches the stage of mature milk, it doesn't mean that it will stay constant from that point on. Mature breast milk continues to change for your baby.

Milk Changes With Each Feeding

At the beginning of a feeding, breast milk starts out as a thin, watery, low-fat milk known as foremilk. Then, as the feeding goes on, it becomes creamier and higher in fat. This creamier milk is called hindmilk.

Milk Changes Throughout the Day

 The concentration of nutrients in breast milk, such as protein, fat, and lactose, are different in the morning compared to the afternoon.

Milk Changes as Your Baby Grows

The amount of breast milk changes as your baby grows, and so do the amounts of the nutrients and immune factors in it. The makeup of your breast milk will be a little different when your baby is one month old compared to when your baby is six months old or one year old.

These changes do not mean that mature breast milk is no longer valuable to your baby after six months or one year. Even though it changes, it is still nutritious and continues to provide many health benefits to older children.

How Long You Will Make Mature Milk

You will continue to make mature breast milk until you decide to stop breastfeeding, or you become pregnant.

After Weaning

Once your baby is fully weaned, or once you stop pumping for your child, the mature milk in your breasts will dry up and go away. However, it can take several weeks or even months until there is no longer any trace of breast milk left.

During a New Pregnancy

If you get pregnant while you are still breastfeeding, your mature milk will change as you get further into your new pregnancy. It will eventually turn back into colostrum for the new baby.

A Word From Verywell

Once mature breast milk comes in, some parents worry about their milk supply being enough for their baby, especially because mature milk has a thinner consistency. But the good news is that breastmilk is created based on supply and demand. The more frequently you feed your baby or pump your breast milk, the more breast milk you will likely make.

If you have concerns about your milk supply or are experiencing delays in your milk coming in, be sure to talk to a healthcare provider or a lactation consultant. They can help you determine if there is something else you should do. Until then, just enjoy the closeness that comes with breastfeeding and trust that your body is doing what it was designed to do.

8 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. KidsHealth from Nemours. Breastfeeding FAQs: Getting started.

  2. US Department of Health and Human Services. Your guide to breastfeeding.

  3. WIC Breastfeeding Support. The phases of breast milk.

  4. KaiserPermanente. Breastfeeding.

  5. American Academy of Pediatrics. How often and how much should your baby eat?.

  6. Lawson MAE, O’Neill IJ, Kujawska M. et al. Breast milk-derived human milk oligosaccharides promote Bifidobacterium interactions within a single ecosystem. ISME J. 2020;(14),635–648. doi:10.1038/s41396-019-0553-2

  7. Langley-Evans S. Nutrition, Health and Disease: A Lifespan Approach (Second Edition). Wiley.

  8. KidsHealth from Nemours. Weaning your child.

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

  • Lawrence RA, Lawrence RM. Breastfeeding A Guide For The Medical Profession Seventh Edition. Mosby.

  • Newman J, Pitman T. The Ultimate Breastfeeding Book of Answers. Three Rivers Press.

  • Riordan J, Wambach K. Breastfeeding and Human Lactation Fourth Edition. Jones and Bartlett Learning.

By Donna Murray, RN, BSN
Donna Murray, RN, BSN has a Bachelor of Science in Nursing from Rutgers University and is a current member of Sigma Theta Tau, the Honor Society of Nursing.