This article explains how breast milk is produced by mums and describes various aspects of breastfeeding related to feeding frequency and changes in your milk.
As soon as you're pregnant, your body starts to undergo the changes that support milk-making – in fact, changes you can feel in your breasts, such as a slight tenderness, and maybe a darkening of your nipples and areola, are among the early signs of pregnancy.
Your breasts contain milk glands, made up of alveoli, which are tiny sacs clustered together and which fill with milk. Once breastfeeding is underway, after your baby is born, milk glands make the milk which is then stored in the alveoli.
What is colostrum?
Colostrum is a concentrated a mixture of proteins, vitamins (such as vitamin A) growth factors, enzymes and anti-infective agents. Colostrum helps your newborn through the first three to four days of life, protecting against infection in their new environment outside the womb and helps expel meconium (the black, sticky poo babies are born with).
A few days after your baby’s birth, the colostrum is replaced by mature milk. This has more water in it than colostrum, and is made in greater volumes. Breastmilk enables your baby to grow and develop, alongside contributing to the development and functioning of the immune system. This is because it contains antibodies and other constituents which help protect against infection.
You produce colostrum, the early milk, sooner than this from about halfway through pregnancy and for the first few days after birth. You may not be aware of it until later pregnancy, and maybe not even then. Colostrum is only made in relatively small amounts, but some women leak a little of it in the final weeks, and you may see evidenece of this when it dries on your skin.
The let-down reflex – making milk available
When your baby starts sucking at your breast, the hormone oxytocin is released, causing the tiny muscle cells around the alveoil to contract and squeeze out breastmilk. This ‘squeezing’ is known as the let-down reflex.
Some mums feel the let-down reflex as a tingling sensation in the breast. There may be a number of ‘let downs’ every time you breastfeed, and you may or may not be aware of them.
Mums start mature milk production as soon as their baby is born – and that happens whether their baby is ever placed at their breast or not. You may notice this surge in production as your milk ‘coming in’, any time between day two and day five or six after the birth – your breasts may look and feel fuller than before.
After this initial production, you continue to make milk as a result of milk being removed from the breast - your baby drinking the milk or by you expressing it, using your hands or a breast pump.
When breastfeeding is going well, this is what ‘drives’ the milk supply – as milk is removed, your body gets the ‘signal’ to make more. Your baby will never fully ‘empty’ your breasts – if they feed a lot, your body makes more in response. If you feel you are not making sufficient milk, read our article for help and support.
Babies very typically feed frequently, anything from eight or nine times in 24 hours to 15 or 16 times, often in ‘clusters’ of feeds with small gaps in between, so actually counting the feeds is not really possible – you might not know if your baby is starting a new feed or ending a previous one. That's fine – with a healthy, thriving baby this is normal.
Your baby and your breasts work in harmony, with your breast milk production matching their needs, so when your baby ‘asks’ for more milk, and you respond, the milk is there. Increasing breast milk supply happens naturally in response to the increased needs of your baby: the more milk needed and the more milk removed, the more you make.
Frequent feeding not only stimulates milk production, it also supports emotional and social development. Every time your baby feeds, you are enabling a shared connection – this helps your relationship, and your baby’s feelings of security.
Changes in your breast milk
The fat content of your milk gradually increases as the milk is removed, so when breasts are relatively less full, the fat content is proportionately higher; when your breasts are relatively more full, the fat content is proportionately lower.
Healthy, effectively feeding babies will get the right milk intake and type of milk for them. This also means you don’t need to worry about whether your baby is getting a certain amount of ‘foremilk’ (the name given to the lower fat milk) and ‘hind milk’ (the name of the higher fat milk).
Sometimes, mums wonder if their baby has been on the breast long enough to ‘get the hindmilk’….in fact, you hardly ever need to be concerned about this. The baby, and your breasts, sort things out for themselves, as long as you feed responsively and in tune with what your baby seems to want.
When your baby seems to have had sufficient on one breast – shown by coming off the breast, or slowing right down – you can switch sides and offer the other breast. Not all babies take both sides each time or any time; and they’re happy with one; some babies show they want three or four or more sides at a session.
NCT supports all parents, however they feed their baby. If you have questions, concerns or need support, you can speak to a breastfeeding counsellor by calling our helpline on 0300 330 0700, whether you are exclusively breastfeeding or using formula milk. Breastfeeding counsellors have had extensive training, will listen without judging or criticising and will offer relevant information and suggestions. You can also find more useful articles here.
National Breastfeeding Line (government funded): 0300 100 0212
UK Association of Milk Banking has information on its network of milk banks across the UK.
Best Beginnings: view video footage online from 'bump to breastfeeding'.
Healthtalkonline.org provides a comprehensive library of face-to-face interviews where parents share their experiences about breastfeeding, birth, parenting and many other issues.