Colostrum is the first milk your body makes. It begins being produced during pregnancy and increases in volume when baby is born, placenta is delivered and stimulation commences. It's usually thick, sticky, and can range from clear to yellow or golden in colour. 

Because of the small quantity, one of the biggest concerns new parents have is whether their baby is getting enough in those first few days. Those small volumes are exactly what most healthy newborns need. A newborn's stomach is tiny at birth, and colostrum is incredibly concentrated. It is packed with antibodies, immune factors, growth factors, and nutrients that help protect your baby while their own immune system is still developing.  

Around day 2 to 5 after birth, many parents notice their breasts feeling fuller, heavier, or warmer. This is often the point where people say their "milk has come in." What is actually happening is that colostrum is gradually transitioning into the next stage of milk production known as transitional milk. 

During this time, milk volume increases significantly as your body responds to the hormonal changes and breast stimulation occurring after birth. The milk often starts looking whiter and creamier than colostrum, and babies may begin taking larger volumes at feeds. Transitional milk contains increasing amounts of fat, lactose, and calories while still providing important immune protection. This stage helps to support the rapid growth that occurs in the early weeks after birth. 

The transition can appear to happen quickly, with parents often going from wondering if they have enough milk to suddenly feeling very full and engorged. Often babies can become fussy as the breast becomes more full, and feeding can feel overwhelming. This is just a normal transition and its important to be kind to yourself and seek support if needed.  

Mature milk  

By approximately 2 to 6 weeks postpartum, milk is generally considered mature milk. Despite its name, mature milk doesn’t remain the same. It continues to change from feed to feed, throughout the day, and across months and years of breastfeeding. 

Mature milk is made up of approximately 87% water, which is why exclusively breastfed babies do not require additional water, even in warm weather. The remaining components include carbohydrates, fats, proteins, vitamins, minerals, hormones, enzymes, and immune factors that work together to support your baby's growth and development. 

As your baby grows, the composition of your milk continues to adapt to meet their changing needs. Whether your baby is a newborn, an older infant, or a toddler, your milk remains uniquely designed for that stage of development. 

Your milk also responds to illness and infection. Breast milk contains living components that help support your baby's immune system when they are exposed to viruses and other pathogens. This ability to adapt is one of the many reasons breastmilk continues to provide benefits well beyond the newborn period and throughout the entire breastfeeding journey.