How does breastfeeding work?

How breastfeeding works – Transcript

In the last 50 years we’ve learnt a lot about breast milk, and also about how the process of breastfeeding works. So in this video I’d like to talk you through some useful facts that will help you to understand this process better, and one of the first things is to talk about breast size. We know that breasts come in all different shapes and sizes – and that’s absolutely fine for making milk.

A lot of women feel concerned if they have what they consider to be a flatter chest (breasts), and worry that they won’t be able to make enough milk for the baby (boosting supply) but generally, that is not true at all. And so whether you are large breasted or not, your body has all the functioning ability to make as much milk as your baby needs, no matter how big or small a baby is too.

So let’s look at the external structure of the breast – so we’ve said already that the breast comes in different shapes and sizes. The nipple is surrounded by an areola which is the dark area around the base of the nipple, and this has a great blood supply. It also has sweat glands and sebaceous glands which lubricate.

It has Montgomery’s Tubercles also, which we know alters the PH of the environment of the nipples, so that it’s hostile to bacteria, and this is why you don’t have to wash your nipples every time your baby feeds, or before your baby feeds. There is an antimicrobial effect going on there.

And about 20 percent of breast feeding women will say that they’ve seen milk leaking out of these Montgomery’s Tubercles, which look like little bumps around the edge of the areola, and this is normal.

So what about the internal structure of the breast? What we do know is that there are lobes inside, four to seventeen of them on average, and each lobe looks like an upside down bunch of grapes – each central stalk from the bunch of grape-like (structures) will lead to a hole in the end of the nipple. So if you have four of those lobes in your breast, you’ll have four openings at the end of your nipple – and if you’ve got seventeen, you’ll have seventeen – and it does vary from woman to woman how many of those you have.

Now I want you to think about each grape-like structure – that is made up of many cells, and it’s in those cells where the milk is made and then stored within those grape-like structures – and this is true for every single one of these, and there are hundreds of them within the breast.

And surrounding each grape-like structure is a meshwork of cells. Now these are muscle cells, and under the action of a certain hormone, every one of the muscle cells will contract, and in so doing are going to contract these grape-like structures, and in effect, push milk out of the breast. That is what happens when you have a let down of milk.

And while you are pregnant, the milk-making machinery inside your breast, these lobes, start to really grow and proliferate – and there’s also a mega blood supply as well which grows, and the blood supply comes and surrounds each of these grape-like structures, because raw material from your blood is taken from there, and a new substance, breast milk is made. Not everything that is in your blood goes into the breastmilk, but it is a NEW substance, and it needs raw materials.

And also within your breast there is fat which helps to protect the structures inside – there is connective tissue, and there’s a substance called lymph, which helps to take waste away from the breast through the lymphatic system.

A lot of breast feeding women are surprised to learn that their body has been starting to produce milk, colostrum, very early, low volume sticky type milk from sixteen or seventeen weeks of pregnancy. This milk is made in these structures that we mentioned.

So while you’re pregnant, you have a very high level of a hormone called prolactin, and this is the milk-making hormone. But due to the action of some other hormones present while you’re pregnant, it will inhibit prolactin hormone, and therefore not a large volume of milk is made at this stage. Now, once you’ve given birth and particularly to the placenta after the birth, the hormone levels that were inhibiting prolactin, fall dramatically, and the prolactin hormone can then start to make far more amount of milk – and this usually starts to kick in round about 30 to 40 hour mark after the birth.

Before this point the milk that you were making was driven solely by hormones, and this means that even if you weren’t going to breast feed you would still be aware of milk being made in your body and being available. After this point, however, the milk is going to be made according to how much emptying of the breast is going on – and that means your baby needs to be feeding frequently, and according to his needs, to generate that milk.

Asian mother breastfeeding her baby girlIt’s really demand and supply. So when demand goes in at the breast, your body makes more. When there is emptying going on, – i.e every time a little bit of milk comes off the breast, and your baby swallows that, then emptying has occurred, your body then makes more on that particular breast – and that is the mechanism which goes on then right throughout the time that you’re lactating, and right until you finish.

So with this in mind, know that when your baby starts to feed more frequently at the breast – that could be during times of a growth spurt or cluster nursing (normal patterns) whatever the reason, your body will start to make more milk, because that is the way it works.

More demand goes in, your baby gets more, and when there’s less emptying of the breast, your body will make less, and that’s normal as well.

And getting back to that first milk, colostrum, I do have a lot of ladies worried about the amount of milk that they’re producing at the beginning – very very small amounts – and bear in mind that your baby’s stomach size is the size of a marble on day one. So they don’t need lots and lots of volume. It’s correct that that colostrum will be small amounts, and that is normal in biology.

And even by day three your baby’s stomach is only the size of a shooter marble, which isn’t much bigger than that! By 10 to 14 days, it will be the size of a golf ball, which is maybe 65 to 80 mils – so babies don’t need high high volumes of milk. Please don’t be alarmed if you find that in the first couple of days, particularly, you’re producing very small teaspoon size amounts.

And from day two to three after the birth, that’s when you begin to see that the milk supply is increasing – and it’s the volume really that’s increasing. And with that there is changing composition of the milk. So the levels of sodium and chloride and protein, that was very concentrated in the colostrum, tend to reduce, and lactose and other nutrients tend to increase after that time.

And it’s also important to know that when your baby feeds at the breast and has what is considered to be a good feed, comes off the breast looking quite full – your breast is not empty then. There’s always about 25 percent residual milk in the breast at any given time, as long as there is frequent feeding going on, or frequent emptying by a pump, even.

It’s important to know that you don’t have to wait for your breasts to refill, because as milk is coming off, your body is making more. There is a factory scenario going on, so there will always be available milk there. The more drained your breast is, the rate of milk production will be faster, and the less drained, that rate will slow down, and the more drained you breast is, the higher the concentration of fat at that point, because of the low volume, and the opposite of that is also true.

So the rule of thumb is to allow your baby to feed as often and as frequently as he wants (normal patterns) and be assured that he’ll get all the breast milk and all the nutrients that he needs.

So we know that every time a little bit of milk comes after breast, your body makes more on that side. Your baby gets more and your body makes more. So how does that work? Your baby comes to the breast and does fast sucks at the beginning of that feed. Those fast sucks send nerve impulses to the brain that will cause the pituitary gland in the brain to release hormones, oxytocin and prolactin, and these hormones, particularly oxytocin, will act on those muscle cells around the grape-like structures.

And it’s the action of that hormone that causes the contraction of those structures and the let-down of milk. That milk will come shooting down the whole network of ducts leading to the holes in the end of the nipple – so the milk will come, hit the back of your baby’s throat – and when babies feel milk hit the back of the throat, they start to swallow. So your baby will then change his pattern – lots more rhythmical suck, swallow, pauses as he gets that milk.

So some of you will feel that let-down as a tingling. Some feel it a little bit sharper than that at the beginning, but that usually settles down – and some of you will never feel it at all. So whether you feel it or you don’t isn’t an indication of the milk coming down or not. What IS an indication is whether your baby is starting to swallow milk, and you can usually hear baby swallowing. So that is the thing to tune into.

And after your baby has swallowed that milk from that batch, he is then going to have to change the pattern again. Now at the end of the let down the volume is very low, and many babies do a little bit of flutter suckling, and then they work hard again to call another let- down of milk – and so your body can actually produce three to five let-downs on average on one side, if your baby works through that pattern.

Newborn baby breast feeding breastI also want to talk about the breast storage capacity. I did mention earlier that women worry about being smaller-breasted, as if they may not be able to produce enough milk – but we do know that it may mean that your breasts are not able to STORE as much milk between the feeds, and therefore your baby may feed more frequently, but your body can make ALL the milk that your baby needs, irrespective of the size of your breasts.

And larger breasted women may have a greater storage capacity and be able to go longer between the feeds – but once again the body will make what the baby needs.

So from birth, every day, your baby is telling your body to make milk and we never grow so much as we tend to do in that first month or two after the birth, so every day your baby needs extra calories. Your body will make that little bit more every single day. But the amount you make will plateau at about a month – it will be a very similar amount after that, and that similar amount will carry on up to six months. It doesn’t really fluctuate that much, apart from the odd growth spurt and things like that.

So it’s really that rapid thing that goes on over the first few weeks that take a lot of breastfeeding mums by surprise, that frequency of feeding. Everything feels so intensive, and this can feel relentless (supporting a breastfeeding mother) but it is normal in biology, and once you’ve got past that first four to six weeks, things do tend to settle down, although patterns will keep on changing, but generally there is a good change.

And finally please be assured that your supply is always in a state of flux at any one time – and breasts work independently as well. I have known women who have breastfed from only one side for months. Your body can do that as well, but know that there WILL be dips in supply at times, and there’ll be increases, and you can boost your supply, and you can deliberately reduce it if you want to. That is the way it works – and the more you understand the mechanism, the more confidence you’ll have. So I hope that you will look at related videos too, to get a fuller understanding, and to be able to move forward with your breastfeeding.

Review dates, references & further resources

Review Dates

Version 1.1 published in March 2019. Next review date: Jan 2022


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