Breast Milk: Answers to Common Questions

Mother breastfeeding baby girl at home in New York City

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Breast milk is a liquid source of food made by a mother's breasts. A woman's body creates it in response to pregnancy and the suckling of a baby at the breast—but women who have not been pregnant can also breastfeed, with the help of hormones, medications, and stimulation such as pumping.

Breast milk provides a child with complete nutrition, as well as protection against infections, diseases, and illnesses. Breastfeeding benefits mothers and children in a variety of ways, and many of the health benefits continue long after breastfeeding has ended.

What Is Breast Milk Made Of?

The composition of breast milk is complex. It consists of over 200 different substances, including protein, fat, carbohydrates, vitamins, minerals, other nutrients, enzymes, and hormones. This composition isn't constant. It's different from mother to mother. It even varies within the same mother, depending on the baby's needs.

Breast milk changes during each feeding, from one feeding to another throughout the day, and over time to meet the needs of a growing child. For example, if your baby has an infection, your breast milk may provide immune cells to help fight the illness.

When Is Breast Milk Produced?

The production of breast milk begins during pregnancy. When your baby is born, you will have a small amount of milk for the first day or two. Don't worry; this little bit is more than enough for your newborn. Your baby is getting enough milk if they have one wet diaper on day one, two wet diapers on day two, and so on.

By the third day after delivery, the production of breast milk increases. As your breast milk comes in, you should feel your breasts begin filling up. However, it could take longer (up to five days) for first-time moms .

Breast Milk Stages

In the first two weeks after a baby is born, breast milk progresses through three main stages: colostrum, transitional breast milk, and mature breast milk.

Colostrum is the first breast milk. It's present at the end of pregnancy and during the first few days after a baby is born. It's usually thick, yellow and sticky, but it can also be thin and white or orange in color.

If you are pumping, beware of the colostrum getting stuck in the tubing of your pump due to its thickness. It may be easier to hand-express into a small cup to make sure your baby gets this antibody-rich milk. (You should still use your pump to stimulate your breasts and encourage milk production.)

Colostrum is easy for newborns to digest. It's high in protein, low in fat, and contains a high concentration of antibodies, specifically Immunoglobulin A (IgA), as well as white blood cells, to fight off infections.

It's also a natural laxative that helps prevent jaundice by clearing your baby's body of meconium: the first thick, black, tarry poop. The amount of colostrum that your body makes is small, but that small volume contains everything your new baby needs in the first few days of life.

Transitional breast milk is a combination of colostrum and mature milk. When your breast milk begins to come in (three to five days after delivery), it mixes with colostrum and gradually transitions to mature milk over the course of a few days or a week.

Milk then changes over to mature breast milk by the time a baby is about two weeks old. Mature breast milk is a combination of foremilk and hindmilk. When your child latches on to nurse, the first milk to flow out of your breast is foremilk. Foremilk is thin, watery, and lower in fat and calories. As you continue to breastfeed, hindmilk will follow. Hindmilk is thicker, creamier, and higher in fat and calories.

What If I Don't Make Enough Breast Milk?

Your body begins to make breast milk in response to pregnancy and delivery of your child. But to continue to make breast milk after your baby is born, you have to breastfeed or pump your breasts. The more you breastfeed or pump, the more you'll be telling your body to make breast milk.

Almost all mothers have the ability to make a healthy breast milk supply. If you're worried about or struggling with a low milk supply, get help from a physician, lactation consultant, or breastfeeding support group such as La Leche. Most of the time, correcting your baby's breastfeeding latch and breastfeeding more often will help.

Why Is My Breast Milk That Color?

The color of breast milk can change throughout the day, or from one day to the next. It's usually white, yellow, or bluish. But,depending on what you eat, it could have a green, orange, brown, or pink hue.

Occasionally, blood from rusty pipe syndrome or cracked nipples can appear in your breast milk. It may be scary, but it isn't dangerous. As long as your baby is not refusing the breast, it's safe to continue to breastfeed if your milk changes color.

What Does Breast Milk Taste Like?

Breast milk is described as sweet and creamy. It gets its sweetness from the milk sugar lactose, and it's creamy due to the amount of fat it contains. The foods that you eat each day as part of your breastfeeding diet will also contribute to the flavor of your breast milk. 

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Article Sources
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Additional Reading
  • Breastfeeding and the use of human milk. Pediatrics. 2012;129(3):e827-41. doi:10.1542/peds.2011-3552

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

  • Lawrence RA, Lawrence RM. Breastfeeding A Guide For The Medical Profession 8th ed. Elsevier Health Sciences, 2015.

  • Riordan J, Wambach K. Breastfeeding and Human Lactation 4th ed. Jones and Bartlett Learning, 2014.