Without a sense of this rapid increase, a mum who has been advised that her baby isn't gaining well can be very confused if her HCP advises that she should give a certain volume of supplemental milk (ideally expressed milk) which to her seems much larger than the marble she may have in her mind.  In consults I've met women who had been advised they needed to increase supply but were contacting me as they felt their supply was fine, due to the fact that they could always express some milk.  When we discussed the volumes expected by day x the mums' were sometimes quite shocked at the volume expected and it allowed them to make sense of the advice given.  Of course there are also cases where parents are advised to give large supplements which aren't needed, and in any case where low weight gain is an issue, the first step is to evaluate and improve feeding.  Poor weight gain is an indicator of a feeding issue to be resolved, and although supplementing may be part of the solution, it is also sometimes suggested where not needed.

The purpose of this blog isn't to detail where and when supplements might be needed or how they should be given - those situations are as individual as each family.  This blog is designed to give an overview of how much milk a mum can expect to produce if a baby is drinking well over the first 10 days, or how much she can roughly expect to express (if exclusively expressing), and perhaps to make some sense of the volumes that parents may be asked to supplement.

This is where we first have to address the issue of the shooter marble at birth and some misconceptions around it.  The marble is used to illustrate a volume of around 7 ml, as research suggests this is an average volume in  a typical feed of colostrum may on day 1 [1].  

This 7 ml is the size of a feed, i.e. the volume of colostrum typically consumed.  It is not the size of a newborn baby's stomach.  In fact a newborn stomach is more likely to be around 20ml according to Nils Bergman's research [2].  A feed of colostrum does not fill the stomach to capacity at birth, nor does it provide the full energy requirements of a baby on day 1- but it is not designed to.  A baby is born with a store of glycogen to use as an energy store.  After birth hormones are released in order to liberate the glycogen store to provide the baby with extra energy.  It is estimated that 70% of the glucose requirements for the brain are met by this glycogen with the remainder coming from milk feedings and also from ketones in fat stores [1].  This is why a baby loses some weight after birth.  Again, it is by design that the fat stores are used to provide energy for the first day or 2, until larger volumes of milk are being produced and consumed.  Whereas some might suggest that babies should be given formula in order to ensure all their energy requirements come from a food source and therefore not have such a drop in weight, the research suggests that this actually affects their ability to access alternative sources of fuel, such as ketones, in their own body ([3][4][5]).

This actually has a long term effect.  Although formula fed infants do use less fat stores, and therefore lose less weight, research has found that formula fed babies who gain significantly more weight in the first week than breastfed babies are at greater risk of obesity several decades later.  The researchers suggested that this first week was a period of "chronic disease programming"  [7].

Over the course of the first day intake could vary significantly depending on how often a baby feeds, and how well each feed goes.  Babies can be quite sleepy after birth perhaps due to labour drugs or birth interventions, and whereas one baby may only be feeding 6 times in that first 24 hours, another baby with a straight forward birth who doesn't have separation from mum and is held skin to skin may feed 12 times or more.  Those babies can clearly be taking in quite significantly different amounts of milk.  Research shows a range in the first 24hr of 7-123 ml [1].  These are hugely different calorie intakes.  Allowing calories of 53.6 kcal per 100ml in colostrum  [8] a baby taking in only 7ml over a whole day is receiving just under 4 calories from food.  A baby taking in 123ml is receiving about 66 calories.  Those 2 babies will have very different demands from their glycogen and fat stores to make up the required calories.  Walker lists the average colostrum intake over the first 24 hours as 37ml.  The more frequently that a baby feeds in the first 24 hours the more calories are available to baby, less fat stores are needed, and thus weight loss reduces.

In the days following birth the level of progesterone in the body from pregnancy drops.  This increases the volume of colostrum.  On day 2, milk intake is much higher than day 1.  One study details an average of 185ml over day 2, with a lower range of 12ml and an upper range of 379ml [9].    This would be an average of perhaps 15-20 ml in each feed.  Another Dutch study listed in Walker's book [1] placed the day 2 intake at 44 - 335ml with an average intake of 14ml at each feed Milk production has effectively doubled between day 1 and day 2.

It is common for milk volume to increase significantly around day 3.  In lactation texts this is referred to as "the onset of copious milk production" or "secretory activation".  Many people refer to it as "milk coming in".  At this stage progesterone has dropped to a level that allows the walls of the breast ducts and alveoli to become more 'watertight' and to contain more milk (discussed more in this previous blog).  Milk volume increases dramatically from this point onwards.  Average milk intake on day 3 is 408ml [1] with a lower range of 98ml and upper range of 775ml), which may work out as approx 30-50ml in each feed, again effectively doubling from day 2.  At this stage women often feel their breasts as being much fuller and often start to become aware of having milk ejections (or letdowns) while feeding.
Although it is common for milk to come in on day 3, it can be delayed by a day or 2 for many reasons.
Milk volume is also affected by whether it is a first baby or a subsequent baby.  One study found that women who had previously breastfed were around 1 day ahead of first time mothers in terms of milk volume, producing 142ml more on day 3, so volumes can vary stubstantially.

Day 4 sees another increase to an average of 625 ml a day [1] (lower range 378 ml and upper range 876 ml), which may be around 50-70ml in each feed if you assume 8-12 feeds a day.  Nils Bergman however suggests that a physiological feeding pattern is for a newborn is to feed roughly once an hour taking around 20-30ml in each feed.  This would give a similar volume of around 600ml.  The amount of milk a mother has on day 4 is predictive of her milk supply going forward (unless there is an intervention to change volume).  One U.S. study looking at exclusively expressing found that milk volume on day 4 was predictive of milk volume at 6 weeks [10], so a good supply on day 4 is a good prediction of good volume weeks later.

Milk volume continues to increase after day 7 to around 800ml a day which would be considered a full supply.  Some women may be producing 1000ml or more, and obviously those feeding twins or other mutiples will be producing significantly more if breastfeeding exclusively.

It's also only when you consider the incredible change in volume in the first week that we can often start to make sense of volumes that are suggested when giving milk from bottle / cup /syringe etc.  If a baby is not latching on day 5 and a HCP suggests giving 60 ml of milk (ideally expressed breastmilk) every 3 hours, this can seem like a large amount for a baby born only 5 days ago if your memory holds an image of a shooter marble.  It's only when you consider that a baby may be drinking 20oz on day 5 that this makes any sense.

As the studies show, the milk intake can vary massively from baby to baby.  A woman who has breastfed before, who had an uncomplicated birth, baby latches well and is feeding frequently may be producing significantly more milk in the first few days than a first time mother who had separation from baby after birth, is having problems with baby feeding, and/or there is infrequent feeding.  Birth weight will make a difference too.  A 9lb baby is going to have different energy requirements than a 6lb baby, and will therefore have different milk needs.  A 9lb baby may indeed be drinking 600ml of milk on day 5, and a 6lb baby may be drinking 500ml.  Both may be having their calorie needs met.  In contrast though a 7lb baby who hasn't been breastfeeding well and is drinking less than 500ml of milk on day 5 may be losing weight, or at least not gaining weight.

All of these factors can lead to very different pictures of weight loss and weight gain after birth.   We do expect babies to lose some weight after birth, due to using up fat stores.  They will also lose some weight due to fluids, and if a mother was given IV fluids during birth this may increase weight loss.  This is normal and expected and in breastfeeding forums I often see conversations about weight loss of up to 10% being ok.  This is both true and not true.  It's true that weight loss of over 10% requires intervention, but it's not true that weight loss of 9 or 10% would be considered average and therefore we shouldn't be concerned about it.  The average weight loss of a baby is 5% - 7% with the lowest weight occurring around day 3 or 4 - essentially just before "milk comes in".  According to the Academy of Breastfeeding Medicine:

Once milk comes in and babies are drinking larger volumes weight should start to increase.  This previous blog on weight gain discusses the expected pattern in detail, but in short a baby is expected to gain around 30g a day from this point, with 20g a day being the lower end of normal.  A baby who is gaining under 20g a day is also considered at need of intervention.  That intervention may be correcting positioning and attachment so that a baby gains better.  It may be feeding more frequently and/or swapping sides more frequently.  It may be expressing to increase milk supply and topping up feeds with the expresssed milk.  In some cases it may be using supplemental donor or formula milk temporarily while building up supply by feeding and expressing.

There were a few things that prompted this blog.  I've been mulling it over for a few months as I frequently find the same conversations popping up in breastfeeding forums.  Conversations where a HCP has suggested top ups (say 50ml) for a baby who isn't gaining as expected and some reply to say that babies have tiny stomachs and don't need this volume.  Others comment to say that giving that amount of top up will decrease her milk supply.  While both of these may be true in some situations, they are not in others.  A 2 day old won't need milk feeds of 50g.  Giving a 4 day old baby 50ml feeds of a milk other than mum's milk without building or sustaining her milk supply will impact milk production.  A one week old baby who is gaining 15g a day probably doesn't need 50g topups after each feed either - optimising breastfeeding would likely be enough to shift that baby into normal range.  On the other hand, a baby who is 10 days old, hasn't gained any weight since birth, is sleepy, is 11% below birth weight and a breastfeeding assessment shows very little milk transfer at the breast may need that much larger supplement while the breastfeeding problem is resolved and mum works on increasing milk production.  Each situation is very different and breastfeeding parents are often quite unaware of just how much milk their baby needs to regain birth weight or how quickly the volumes should increase.  I often see other conversations on forums or talk to parents who feel they have plenty of milk because they can express 30ml.  That 30ml expression may be a sign of great supply on day 3 or 4.  It may also be a good sign at 3 weeks immediately after a good effective breastfeed,  but is much less reassuring at 3 weeks if expressed 2-3 hours after the last feed/expression particularly in conjunction with a baby who is gaining perhaps 2 oz a week.

So I suppose the takeways I want to get across with this blog are these:
Yes colostrum is in very small quantities in the first day or 2 but it ramps up extremely quickly if all is going well, and consequently the amount that a baby drinks ramps up very quickly too.  We do expect a baby's weight to drop after birth, and it is by design, but by day 5 a baby should be gaining weight and ideally should gain at around 30g a day and to do this there needs to be significant milk intake.  The earlier and more frequently a baby breastfeeds in the early days the better this will be for milk production, which is why mothers are encouraged to start expressing early and often if their baby is not latching.  This blog is not meant to scare people about volumes.  I can understand why someone may be sitting in a hospital on day 1 reading this with a non latching baby, worried about only being able to express one ml at each expression session.  To you I want to extend reassurance.  Often parents are told to express and feed every 3 hours, but as I explored in a previous blog - this means at least every 3 hours.  If you express 1 ml every 3 hours you might get 8ml over the course of the day.  If you express every hour however, you may get closer to 24ml (remember the lower range found in the study above for day 1 was 7ml so it is also normal to have less).  The more you express, the better stimulation you provide and the better your milk volume will be on day 2 and day 3 etc.  Once your milk comes in around day 3, you will also likely find expressing much easier.
If your baby is at day 6 or 7 and isn't yet gaining weight you will likely be advised to start expressing in addition to breastfeeding to help raise your supply.  The volumes I have mentioned above of 600ml a day at 1 week may seem enormous when you look at your expressed milk.  The good news is that milk production really does ramp up extremely quickly when given the right stimulation.  If your baby didn't manage to get all the stimulation needed in the first few days then expressing can resolve that.  Hormones are primed for milk production in the first couple of weeks, and getting an expressing routine going can turn things around entirely in a few days.  Just as an effectively feeding baby can build milk production from a few mls to 600ml in a week, so can a pump.  The first 2-3 weeks are the easiest time to very quickly build milk supply to volumes that are needed, and sometimes expression is needed for a baby who didn't get the best start and isn't feeding effectively.  Raising supply through pumping can actually help a baby to feed better (bigger volumes flow more freely).

Babies do need significant quantities of milk in the latter part of first week and beyond, and weight gain is the best indicator of whether they are getting enough milk.  If everything is going well and all feeding is at the breast, you'll likely have no idea of the amazing volume your body is producing.  If weight gain isn't going well then your baby may need some help in getting your milk production built up as needed.  Now, there's no doubt that in some areas here in NI top ups are suggested far too quickly and it may be that far too large topups are suggested in some cases, but it's also true that sometimes supplemental milk is needed and the volumes may surprise you if you have been told that babies only need a few mls of milk.  Those who work in breastfeeding support walk a fine line when suggesting that more milk is needed.  We want babies to get the optimum amount of milk.  We want that to be at the breast.  We want mums to have a comfortable, enjoyable breastfeeding experience and to have an ample supply of milk.  If a baby is struggling with weight gain we want to find the best way to preserve breastfeeding, to build the milk supply while also giving baby adequate calories.  That involves the minimum amount of supplement needed, but enough to move weight gain into the normal range.  In some cases a comment on a forum telling a mum to feed more frequently rather than give a top up may be correct.  In other cases however that might cause a poorly feeding baby to expend more energy at the breast, further impact weight gain and not raise milk production.  A solution that worked for one mum, will not be the right solution for another who is in very different circumstances that may not have been described clearly on a forum post.  Encouraging a mother to Ignore suggestions to express and/or supplement can be damaging, as can not having good truthful support about when extra milk is needed.  Intervening to raise supply early is usually simple, whereas letting things run without intervening can lead to babies not having regained birthweight at 6, 7, 8, or even 9 weeks and this is when the outcome for breastfeeding is deeply impacted.  It is relatively easy to significantly increase supply with the right stimulation in the first 3 weeks.  It is much more difficult after 6 weeks, so getting early support with breastfeeding is key.

If you are concerned about milk intake, or your baby's weight gain ask for a breastfeeding assessment from your HCP or look for a local IBCLC (International Board Certified Lactation Consultant) or breastfeeding counselor to check if there is an issue which might need some extra support.  When there is a weight gain issue generally all that is needed is support around helping baby to feed better at the breast, and perhaps increasing the frequency of feeds.  If top ups are suggested discuss a plan with your caregiver.  The plan shouldn't just be about those top-ups, but should be about increasing supply so that you can then move back to exclusive breastfeeding.  Expressing and supplementing breastfeeds are almost always temporary if you have the right support.

When everything is going well with breastfeeding and you are feeding exclusively at the breast you will have no idea just how much milk your baby is drinking, but if our breasts were transparent or we had volume measurements we may be very surprised at just how generous our overflowing milk ducts are!