How milk production works
Milk production works on a supply and demand basis. The more you feed, the more you produce. Here is how it works:
The first few days
You begin making your first milk, colostrum, around the middle of your pregnancy. This is caused my increased levels of the milk-making hormone ‘prolactin’. Some women notice this milk leaking whilst they’re still pregnant, but others might not notice it’s there at all. In the first couple of days after your baby’s birth, colostrum is all they need. A newborn baby’s stomach is yery small, so they only need about 1-3tsp of colostrum per feed to fill them up. Offer your baby the breast whenever they start showing hunger cues, and your milk supply will grow over the next few days to meet their needs. Expect to feed your baby at least 8-10 times in 24 hours (and often considerably more!). Some babies are very sleepy in the first few days, so you may need to wake your baby to feed them.
When your milk ‘comes in’
Whilst you are pregnant, your levels of prolactin rise to around 20x the normal level, but your placenta is producing lots of the hormone ‘progesterone’ which inhibits prolactin and stops your breasts making too much milk before you need it. After you have birthed your placenta, your progesterone levels drop dramatically. This causes your breasts to go into overdrive and produce copious amounts of milk by around 3-5 days after birth. For some women this happens gradually, and for others it happens rather suddenly. It is hormonally driven and will happen whether you have been breastfeeding your baby or not. This is often referred to as your milk ‘coming in’, though as I’ve already explained, you are already producing milk for your baby before this happens! Your milk now begins to change from colostrum to mature milk.
Everytime you feed your baby your prolactin level spikes, triggering your breasts to synthesise more milk. Feeding your baby responsively will allow your breasts to establish a good supply.
When your supply is established
From around 6 weeks, your milk supply is established. It is now largely maintained by a protein called the ‘Feedback Inhibitor of Lactation’ (FIL). FIL is a whey protein in your milk which tells your breasts to slow down milk synthesis when they start getting full. When there is lots of milk in your breasts, there is lots of FIL and so production slows down. When your baby feeds, they remove some of the milk and some of the FIL along with it, so production speeds up.
Understanding storage capacity
The amount of milk you can hold in your breasts at any one time is individual to you. Some women can only hold an oz or 2 at a time, some can hold as much as 20oz. The amount your breasts can hold is called your ‘storage capacity’. This is different to your overall supply, which is the amount of milk you produce over the course of a day. The size of your storage capacity does not effect your overall supply. Small or large, you will still produce enough milk for your baby.
The size of your breasts is not an indication of your storage capacity. Your breasts are made up of glandular tissue (where the milk is made and stored) and fat, and the proportions between these tissues vary from woman to woman. You could have very small breasts and a large storage capacity, or very large breasts and a small storage capacity, or vice verser.
A woman with a smaller storage capacity will have to feed her baby more frequently than a woman with a larger storage capacity, because their baby will be taking smaller amounts at each feed. This is why it is so important to feed your baby as and when they need to, rather than feeding them in a routine set by the clock. If a woman with smaller storage capacity goes a long time in between feeds, the level of FIL in her breasts will be high for a long time and her supply will drop.
Trust your baby and trust your body. Your baby will tell you how often they need to feed, and your body will produce milk to meet their needs.
How do I know if I have a good supply?
The main indicators of your milk supply are your baby’s weight, their behaviour, and their nappy output.
Below is an assessment tool made by the unicef breastfeeding friendly initiative to help mothers assess if their baby’s nappy output is normal. This can be downloaded here.
A baby who is getting enough milk will be:
- Feeding at least 8-12 times in 24 hours
- Usually feeding for between 5 and 45 minutes at each feed (though the duration will vary and cluster feeding is normal)
- Generally happy and relaxed whilst feeding
- Finish most feeds themselves and be content for some period after most feeds
- Will have a normal skin colour
Your breasts should be comfortable during feeds and your nipples should be coming out the same shape and colour as they went in. If breastfeeding is painful, you might need to tweak your baby’s latch to make sure they are feeding effectively.
If your baby’s nappy output or behaviour is indicating that they might not be getting enough milk, speak to your midwife or health visitor, your local breastfeeding supporter, or call the national breastfeeding helpline on 0300 100 0212.
Your baby’s weight
Your baby will have a growth chart to track their weight. In the UK, these are based on WHO guidelines for healthy, full term breastfed babies who’s mothers do not smoke. These growth charts are split into centiles. It doesn’t matter too much which centile your baby falls in, that just tells you where they compare to the ‘average’ baby. Being in the 50th centile just means that 50% of healthy babies are bigger, and 50% of healthy babies are smaller. What matters is how they follow the curve of their centile. It is normal for babies to wiggle a bit accross the chart and to cross a centile line, but crossing two or more could be cause for concern. Your midwife and health visitor will keep an eye on your baby’s weight for you and will let you know if anything is amiss.
It is normal for babies to lose weight in the first 2-4 days after birth, but losing more than 10% of their birthweight can sometimes be cause for concern. Most babies who are feeding well should be back up to their birthweight by 2 weeks old, and will gain around 7-10oz a week for around the first 3 months.
The amount you can express is no indication of your supply
Some women just aren’t very responsive to expressing. There are women who can’t express a single drop, and some women who can get 10oz a time with their breastpump. That doesn’t necessarily mean that one has a better supply than the other. A baby who is latching effectively is generally much more efficient at getting milk out than a breastpump, so please don’t worry if you are unable to express much.
Frequent feeding is not a sign of low supply
Young babies breastfeed A LOT. Breastmilk is digested quickly, so their tiny tummies need filling frequently. As explained above, some women have a smaller storage capacity and need to feed their babies more frequently. This is NOT a sign of low supply.
Babies feed for lots of reasons. They feed when they’re hungry or thirsty, but they also feed when they are lonely, scared, tired, or uncomfortable. Breastmilk doesn’t just provide nutrition to your baby, it provides comfort, love, protection from illness, and warmth. The transition between the womb and the big wide world is huge, and breastfeeding helps them to adjust. It is normal and healthy for babies to breastfeed for comfort.
Sometimes your baby will suddenly start wanting to feed more frequently than normal, or will cluster feed (have lots of short feeds close together, acting fussy and coming on and off the breast for a couple hours). This is your baby’s way of upping your supply. It is normal and does not mean that you are not making enough milk. See more information about growth spurts here, and more info on cluster feeding and fussy evenings here.
Feeling less engorged is not a sign of low supply
In the first few weeks, your breasts are likely to feel very full in between feeds. Once your supply is established this tends to settle down. Your breasts learn to only make as much milk as your baby needs which means your breasts might not feel so full anymore. This is normal and does not mean that your supply has dropped.
Your baby happily guzzling down a bottle after a breastfeed is not a sign of low milk supply
It is pretty much impossible to overfed a baby from a breast, but it is very easy to do so with a bottle. Drinking milk from a bottle uses different mechanisms to breastfeeding. If a bottle teat is placed in a baby’s mouth they will often reflexively suck on it even if they are not hungry, just like a baby will suck on a dummy if they’re not hungry, and they will also reflexively swallow any milk that comes out. This is why using top ups of expressed breastmilk or formula is a good way of getting extra milk into babies who medically need it, because chances are they will accept it even if they’re not hungry. It is also why it is important that babies are not given top ups unless it is medically indicated. If a baby who doesn’t need any extra milk is given some anyway, it is likely that they will reduce the amount of breastfeeds they have. That will lead to a drop in your supply, leading to more top ups, leading to less breastfeeds, leading to a drop in supply, and so on. This is a cycle which can lead to a loss of breastmilk supply and is often called the ‘top-up trap’:
Baby’s feeds becoming shorter is not a sign of low supply
As babies get older, they usually get more efficient at feeding and finish their feeds faster. As long as your baby is gaining weight OK and having plenty of wet and dirty nappies, this is not a sign of low supply.
No longer feeling your let down (milk ejection reflex) is not a sign of low milk supply
Some mothers never feel their let down at all, and for most the feeling becomes less intense or disappears altogether over time. This doesn’t mean that it isn’t still happening! Right from the beginning, most mothers will only feel one let down during feeds, but did you know that you actually have up to 9 let downs per feed? Watch your baby. Before your let down, your baby will be taking short rapid sucks. After your let down is triggered, their suck-swallow pattern will become slower and after around 3/4 days you should be able to hear your baby swallowing.
No longer leaking is not a sign of low supply
Most mothers will leak milk in the early weeks (though some may never leak at all, and some may not stop leaking until they stop breastfeeding). Once your milk supply is established and your breasts get used to making only as much milk as your baby needs, you may notice that the amount of milk your breasts leak reduces or stops altogether. This is completely normal and does not mean that you have low supply.