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Stages of Breast Milk

Breast Milk production goes through different stages changing in composition to adapt to your baby’s changing nutritional needs over time.   The starting Colostrum milk known as ‘Liquid Gold’ with its darker yellow colour and high levels of antibodies crucial to protect them from infections.   This then transitions over the next few weeks lightening in colour and becoming thinner into becoming the ‘Mature Milk’  which contains a balance of fats, proteins and carbohydrates to support optimal growth and brain development.



  • Birth to 3-5 days postpartum


    • Thick, yellowish in color.
    • Produced in small quantities (about 2-10 ml per feeding).
    • Rich in proteins, including immunoglobulins (especially IgA), which provide passive immunity to the newborn.
    • Contains high levels of leukocytes and antioxidants.
    • Low in fat and sugar compared to later stages.


    • Helps to establish the infant’s immune system.
    • Acts as a laxative to help the newborn pass meconium, reducing the risk of jaundice.
    • Provides essential nutrients and growth factors.

Transitional Milk

This Transitional Stage is commonly referred to the ‘Milk coming in’ when your breasts noticely swell and can become engorged and hard with milk.


    • 5 days to 2 weeks Postpartum


    • Gradually changes from colostrum to mature milk.
    • Creamier and higher in fat and lactose than colostrum.
    • Volume increases as the milk “comes in.”


    • Continues to provide immune protection.
    • Supports rapid growth and development of the infant.
    • Provides a balance of nutrients and energy.

Mature Milk


    • 2 weeks postpartum onwards


    • Composed of foremilk and hindmilk.
    • Foremilk: Thinner, watery, and lower in fat; high in lactose and protein.
    • Hindmilk: Thicker, creamier, and higher in fat; provides most of the energy for the infant.


    • Approximately 87% water, ensuring the infant stays hydrated.
    • Contains carbohydrates (primarily lactose), fats, proteins, vitamins, and minerals.
    • Dynamic composition that changes according to the baby’s needs and the time of day.


    • Provides complete nutrition for the infant’s growth and development.
    • Continues to provide immunological protection.
    • Contains bioactive components like hormones and enzymes that support the infant’s development.

Ballard, O., & Morrow, A. L. (2013). Human milk composition: nutrients and bioactive factors. Pediatric Clinics of North America, 60(1), 49-74.

Horta, B. L., & Victora, C. G. (2013). Long-term effects of breastfeeding: a systematic review. World Health Organization.

Lönnerdal B et al (2017)  Longitudinal evolution of true protein, amino acids and bioactive proteins in breast milk: a developmental perspective. J Nutr Biochem. 41:1-11.

Pang WW, Hartmann PE (2007) Initiation of human lactation: secretory differentiation and secretory activation. J Mammary Gland Biol Neoplasia;12(4):211-221.

Pons SM et al. (2000) Triacylglycerol composition in colostrum, transitional and mature human milk. Eur J Clin Nutr. 54(12):878-882.

Rollins, N. C., et al. (2016). Why invest, and what it will take to improve breastfeeding practices? The Lancet, 387(10017), 491-504.

Stuebe, A. M. (2009). The risks of not breastfeeding for mothers and infants. Reviews in Obstetrics & Gynecology, 2(4), 222-231.

Victora, C. G., et al. (2016). Breastfeeding in the 21st century: epidemiology, mechanisms, and lifelong effect. The Lancet, 387(10017), 475-490.

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