Breastfeeding basics: perceived low milk supply

Most women are anxious that they have a low milk supply – but it’s actually quite unlikely that there is a fundamental reason for this. Only about 5% of women have a medical or surgical reason that means they are unlikely to produce enough milk. So why does it feel like such a common phenomenon? Here are a couple of thoughts on milk supply anxiety.

Reasons for perceived low milk supply

Misinterpretation of infant cues:

This is a huge reason women believe they have a low milk supply – in fact, in my experience, it is the number 1 reason why women begin to feel under-confident and reach for that bottle of formula.

A newborn baby knows no other reality than his mother. He has been used to being tightly held, rocked, protected from light, noise and temperature variation. He has been surrounded by white noise, drip fed from the placenta, and is never apart from his mother. Suddenly, after a long, and sometimes difficult process for both mother and baby, he is lunged into the harshly lit, loud, cold and wide open space of his crib. It’s the concept of the 4th trimester, and we need to better understand the adaptation from womb to world, to fully read infant cues in the first few weeks.

That baby is unlikely to settle anywhere but his mother’s arms, probably where he feels most at ease is suckling at her breast. Colostrum smells very similar to amniotic fluid, and her breast is near her heart, which he has heard and felt beating for many months. This is partly the reason why many babies feed very frequently, or even non-stop, at some point in the first few days.

In addition, sometimes babies cry. Some babies cry a lot. In some cases – it isn’t clear why they are crying, but one thing we know is that they tend to stop crying when held close with their mother and allowed to breastfeed as often as they like. Now, this is confusing for new mothers, because they perceive most infant crying as a cry for feeds. So they become disheartened that their baby is seemingly unsatisfied at the breast. If they observe women around them formula feeding, they will probably notice that the formula fed babies sleep for longer stretches. They begin to question whether they have sufficient milk, because when they observe their constantly feeding breastfed baby crying unless he is being fed, and another formula fed baby feeding infrequently and settling after most feeds, the apparently logical conclusion they draw is that the formula fed baby is getting enough milk, whereas their baby isn’t.

The reason formula fed babies tend to sleep for longer stretches in the early days (it isn’t necessarily true once a mother’s milk has come in) is that the larger volumes commonly fed to formula fed babies will overfill the newborns tiny stomach. The response to being overfull is either vomiting, or falling asleep – much like adults do after over-eating. It isn’t necessarily a sign of contentment – just a physiological response to the large volume of liquid that the baby now has to digest.

  • So, babies often want to feed constantly in the first 3-5 days – this is normal, and understandable.
  • Women often feel under-confident about their milk supply – there is something absolutely primal about the need to feed your baby, and women’s worst fears are usually that they are starving their baby. This therefore tends to be the first conclusion they jump to.
  • Women, and health professionals, tend to compare breastfed baby behavior to formula fed baby behavior, and they assume that breastfeeding is going wrong when the breastfed baby behaves differently to the formula fed baby.
  • Our society is very used to seeing bottle fed babies now. Health professionals and the public alike generally believe that the volumes fed to formula fed babies are the physiological norm, and therefore breast milk volumes are inadequate.

Differences in required milk volumes:

Formula fed babies drink more milk than breastfed babies. In fact, even babies fed with breastmilk in a bottle drink more than breastfed babies. There are three main reasons for these variations.

1 – Breastmilk is nearly 100% bio-available

Firstly, breastmilk is nearly 100% bio-available. That means that babies can extract nearly all the nutrients from it. In turn, this means that volumes are generally lower, and also more consistent than for formula milk.

The initial volumes are much much smaller than the amounts commonly fed to formula fed babies, and women often compare their expressed milk volumes unfavourably with formula quantities. These small amounts gradually get bigger as the mature milk ‘comes in’. After the initial establishment of a mature milk supply, which takes about 2-4 weeks, a breastmilk supply will remain at relatively constant volume all the way through to starting solids at about 6 months. Babies naturally grow more slowly from about 12 weeks, and the nutritional composition of breastmilk adapts as the baby matures, meaning that they don’t need to keep drinking more and more milk as they get older and bigger. This is in direct contrast to the nutritional needs of formula fed babies, who need more and more milk as they get bigger, because there is a certain proportion of their milk that they simply cannot digest, or extract the nutrients from. This is part of the reason why their stool is smellier, and they are approximately 1kg heavier than breastfed babies by the age of 1 year. This has come to be sign of health and privilege – but actually being heavier at age 1 is associated with an increased risk of diabetes and obesity, so far from being a good thing, it is actually harmful.

2 – Mechanism of bottle feeding

The other reason for increased volumes is due to the mechanism of bottle feeding. When babies drink  from a bottle, they cannot regulate the flow of milk as well. When you have a liquid pouring into your mouth – you have 3 options – 1) drink it, 2) choke on it, or 3) dribble it. So most babies will opt for options 1 and 3, for obvious reasons! So bottle fed babies will drink more milk simply because it keeps flowing into their mouths. The feed is generally fast – so the baby doesn’t get the message that they are full until long after the feed has finished. So we are training our babies to over-eat before they are even responsible for what they eat. We over-ride their full and contented feelings and keep feeding them in order to ‘finish the bottle’. This is also true of babies who are fed expressed milk in a bottle – its just down to the speed and mechanism of suckling that is responsible for this.

3 – Babies receive an increasing proportion of fat as the feed progresses

But the third reason is that when breastfeeding, babies receive an increasing proportion of fat as the feed progresses. They also receive increasing amounts of an appetite-regulating hormone called leptin. Leptin causes the baby to feel satisfied and full at the right time so that the baby doesn’t over-eat. It chemically signals the baby to finish feeding. This is another reason why you should never take a baby off the breast until they spontaneously release the breast themselves. That way you know they have had what they need. It doesn’t mean they wont want the other side of course! It just means they have finished the first side. When you feed a baby expressed milk, the milk does not change as you progress through the feed – it is more homogenized and so babies don’t get that chemical signal in the same way. It is not possible to produce an artificial form of leptin, so it is not present in formula milk at all.

  • Breast milk volumes are initially much lower than the amounts fed to formula fed babies
  • When breastfed babies require supplements for medical or other reasons, people tend to give an amount that is suitable for an formula fed baby
  • Bottle fed babies drink more than breastfed babies – regardless of what’s in the bottle
  • Formula milk does not contain leptin, which regulates appetite and protects against obesity and diabetes
  • The mechanism of bottle feeding does not allow babies to regulate their appetite, or control the flow of milk

So, two of the most common reasons women believe they have a low milk supply are due to the misinterpretation of infant cues, and the fundamental physiological differences in milk volumes between breast and bottle fed babies.

Increasingly we live in a society which loves to compare. It is really important that any comparisons we make are to normalize breastfeeding because this is the biological norm. When we can do this across all sectors of society – the media, health professionals, popular parenting literature – maybe then women will have more faith in their own ability to make plenty of milk for their babies.

By Lyndsey Hookway IBCLC

Lyndsey Hookway is an International Board Certified Lactation Consultant, paediatric nurse and health visitor.
She works within the NHS as a breastfeeding specialist, and also privately through her company – Dreamfeeds.

Only about 5% of women have a medical or surgical reason that means they are unlikely to produce enough milk. So why does it feel like such a common phenomenon? Here are a couple of thoughts on milk supply anxiety.