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Professor Peter Hartmann:
Comparative Lactation: the development of the mammary
gland and maternal/infant development
Western Australia’s unique environment and people
Professor Hartmann’ study of human lactation has been strongly influenced by the Australian environment. Western Australia is one of the few areas of the globe were evolution has been playing out uninterrupted since the dawn of time: the land there has not been submerged by seas, ice, or lava in the past 4.6 billion years. While mammals are a lot less old, the unique geological stability of the western Australian environment awakens the mind, and makes it receptive to the natural treasures it has to offer. These include exceptional types of mammals such as the egg-laying monotremes and marsupial mammals. All use lactation to feed their young, but do so in very surprising ways.
Western Australia’s driest regions are so dry that the average European would survive at most three days without supplies. Yet Western Australian aboriginals have thrived there for tens of thousands of years.
To the unpracticed external eye, these people would seem the poorest of the poor: until very recent times, they lived naked, slept right on the sandy ground, and were equipped with very little more than spears and sticks. Yet their babies have been described as among the most obese on earth1. And despite the lack of hygiene (by Western standards), breastfeeding Aboriginal mothers practically never develop mastitis, a painful infection of the breast that affects 20% of breastfeeding urban Australian mothers.
Why does milk exist?
Monotremes, marsupials, and the outstanding success of aboriginal mothers and babies all contain important clues to reconstruct the story of the development of lactation, and of the usefulness of breast milk.
To reproduce, animals must not only give birth to a new generation. They must also find an adequate supply of foods for their young. Yet the young are rarely equipped to eat all the foodstuffs of an adult. So animals have evolved different strategies to deal with this conundrum.
Many birds migrate huge distances to find breeding grounds where suitable food supplies exist. Some birds, like the kiwi, pack a lot of nutrition into their eggs - so much so that the egg can weigh over half of the weight of the mother. Sharks or salamanders nourish their young with secretions from their egg-laying canals, or oviducts.
Mammals are unique in having developed a skin gland to nourish their young. And this turned out to be a very successful strategy: it allows mammals to raise their young wherever the adults thrive.
The variety of milk is extraordinary, and perfectly adapted to the needs of each baby. The milk of seals, for example, is 42% fat by weight (full-fat cow’s milk is about 3.7%). This helps the baby quickly acquire a thick layer of insulating fat, essential to live on ice – and not melt through it.
Mammalian babies are born at an amazing range of maturities. A baby kangaroo is little more than a primitive embryo. A newborn whale is a comparatively mature animal, able to swim unaided. And these babies develop at very different rates. A human baby takes 150 days to double in weight – but a piglet only takes 10 days.
1
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Since many human babies are fed formula based on cow’s milk, the nursing-sibling of many humans is the calf, not a human. Calves double in weight in a third of the time of humans (50 days). Not surprisingly, cow milk is not an appropriate nutrition for human babies.
The origin of milk
So how did this extraordinary substance, milk, develop?
A clue is given by monotremes, the egg-laying mammals. Unlike other mammals, they do not have nipples. Their milk is produced by glands in the skin and flows out along the hairs.
In the distant past, the ancestors of mammals laid eggs, too. But these are not the solid-shelled eggs we are familiar with. Instead, they were covered with parchment, a skin-like covering that is tough, flexible – and porous. These eggs lose moisture very quickly in dry air. But they can also take it up in humid conditions. Providing such moisture in dry air would have been a very useful survival trait for the ancestors of mammals. And that is why scientists like Oftedal speculate that milk has its origin in this function: to provide moisture, and perhaps even nutrients, to eggs2.
Where did the breast come from?
But where did the glands that make it come from? Skin, after all, is a protective covering. It’s not obviously a source of nutrition.
Another clue is found in the superior wellness of breast-fed babies, who catch far fewer illnesses than those fed cow-milk based formula. Breastmilk is not only a source of nutrition, but of protection too. It boosts the baby’s immune system, allowing it to fight off disease. And that’s where the clue lies: the enzymes that give milk this property seem to be evolved versions of antibacterial enzymes that the skin produces to protect itself. It looks like the protective function of the skin’s glands gave rise to a system that later, much later, became our breasts3. In this view, the first function of these skin secretions was protective - to confer immunity to the infant. Only later did the nutritional function evolve from these proteins.
Why is breastmilk so good?
Making milk consumes a lot of energy: even more energy than is required by the brain, normally our most energy- hungry organ. In evolutionary terms, this is extremely expensive. Nature is
parsimonious. It counts its pennies. Anything wasteful is normally discarded: the genes of an animal that wastes energy will lose out against those of an animal that invests that energy in survival and reproduction.
So something as expensive as breast milk must have a huge, an overwhelming evolutionary benefit. And indeed, human breastmilk is perfect for human babies. But it is also very, very good for
breastfeeding mothers. It may be expensive, in evolutionary terms, but it’s an expense that is worth every penny.
Over the years, studies have shown that babies fed with breastmilk do a lot better than those fed on cow-milk-based formula. They suffer from fewer illnesses; have better visual and motor development; enjoy a lower risk of obesity, and even bear lower risks of diseases like cancer later on in life.
2
Olav T. Oftedal, 2002
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Happily, they also do better at school than their formula-fed peers – an impact that depends on the duration of breastfeeding. The longer a toddler is breastfed, the higher the impact on his grades at school4.
Research has shown that breastfeeding has multiple benefits for the mother, too. They include:
- Faster recovery after childbirth, including quicker weight loss.
- Reduced obesity risk
- Suppression of maternal fertility
Enhanced mineralization of bone, and thus less risk of osteoporosis later in life
- Cholesterol control
- Glucose control, and thus a reduced risk of diabetes
- Reduced risk of breast and ovarian cancer.
- Enhanced self esteem
- Spatial memory and learning show long-term improvement.
And, perhaps most surprisingly, a boost to their IQ5. Pregnancy and breastfeeding unleashes a flood of hormones in mothers’ brains. These make mothers more vigilant and nurturing – and provide great pleasure too. This is an effect observed in mammalian mothers across the board: mother rats, for example, are better at navigating mazes and capturing prey than virgin rats.
Why can breastfeeding be so hard?
With such goodness at hand, the real surprise is that so many mothers find it so difficult that it makes it impossible for them to breastfeed for long. Yet it’s an activity that all other mammals seem to manage without much difficulty. So why are we humans finding it so hard?
Again, there is a clue in Western Australia.
Aboriginal mothers hardly ever suffer from the breastfeeding problems of urban Australian mothers. Why exactly this is remains controversial. But the suspicion is strong that modern lifestyles are to blame. All the points that follow are speculative, and need further research. But they could explain how modernity may hamper good breastfeeding.
In the bush, aboriginal babies always sleep with their mothers, not in another bed or even room as other Australian babies tend to do. As a result, aboriginal mothers may be less tired: they do not have to get up to feed their babies at night, and are not woken by their shrill cries (mothers intervene long before the infant becomes desperate). Indeed, they can feed their babies without really waking up at all. Tiredness is known to be connected with weaker immune defenses.
Another example: the tight, constraining clothes worn by urban women may promote mastitis, cracked nipples and other painful breast conditions practically unknown among aboriginal mothers. Even today, aboriginal mothers rarely wear tight clothes, preferring roomy, airy shirts.
Bad breastfeeding posture, the root cause of many breastfeeding problems, is also unknown among Aboriginal mothers. Unlike urban Australians, they have learnt breastfeeding as children, from the observation of older women. This is an advantage that most urban mothers lack.
Whatever the true reasons, breastfeeding is worth the effort. Mothers’ milk is just too good to pass by. Ask any toddler that is still breastfeeding, as a study by the University of Western Sydney did. They will tell you that breast milk is better than ice cream, sweets, or McDonalds6. “When children were asked about breastfeeding, nearly all said they breastfed because they loved it - they liked the milk and it made them feel happy or good," said the study’s author, Dr Gribble.
4
Fergusson et al, 2000
5
Kinsley C H and Lambert K G (2006), Scientific American 294:58-65
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Catherine Garbin IBCLC & Jacqueline Kent PhD
Linking Science to Practice
Self-confidence: the biggest asset of the breastfeeding mother
Is my baby getting enough milk? Do I produce enough milk? Is my baby feeding normally, or too often, or not often enough? My baby doesn’t sleep through the night, is this normal? My breasts feel too small, am I giving enough milk?
These and similar questions bedevil thousands of mothers and can make their breastfeeding
experience miserable. Dr Jacqueline Kent, a researcher, and Cathy Garbin, a lactation consultant, set out to find reliable answers to these questions based on more than subjective experience.
To do so, they developed a simple, yet elegant methodology to study the production of maternal milk over a 24 hour period.
How does it work?
Start by testing a sample of the milk to ascertain important details of its composition, such as the proportion of fat it contains. Then weigh the baby. Feed it. Weigh it again. The difference in its weight will be the quantity of milk baby has ingested. Finally, take another milk sample, to see how the latter sample differs from the first one. Repeat over a 24-hour period. And analyze the results.
Dr Kent and Ms Garbin carried their study out on 71 Western Australian mothers and babies7. They have reassuring news for mothers: there is a huge variety out there. Individual mothers and babies seem to find their own way to breastfeeding happiness. No matter what measure you look at, it varies a lot. This includes the quantity of milk taken at each feed, the feeding frequency of babies, the proportion of available milk that is removed at each feed and so on. Each of these numbers has a large natural range, typically from 1 to 3. So some babies like to feed six times a day, others prefer 18 times a day.
So, even if your baby has very different habits from those of your neighbour’s, it is likely to be within normal range.
Some examples? Some babies happily get by with 550 grams of milk per 24 hour period, while others take up more than a litre. Some only like to suckle from one breast at each feed, others prefer suckling from both. Some are happy with as few as six feeds per day, others demand up to 18 (sadly for mothers’ sleep, two-third of babies turns out to prefer feeding at night).
But no matter how they feed, babies turn out to take remarkably similar quantities of nutrients. Fat intake, for example, is independent of feed frequency. Babies that prefer fewer feeds take in more milk per feed than babies who prefer more feeds8.
While this variety is in and of itself reassuring, it is not enough to help mothers regain their breastfeeding confidence. Monitoring milk production over a single feed is no help, since babies’ habits vary so widely. Doing it over a 24-hour period can help. But what is most clearly lacking are reliable guidelines that lactation consultants around the world can use.
7
Volume and frequency of breastfeedings and fat content of breast milk throughout the day – Pediatrics (2006) 117:e387-e395
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Catherine Garbin IBCLC & Donna Geddes PhD
Positioning and attachment
Many mothers can experience difficulties while feeding their babies. Traditionally, they have turned to lactation consultants for help. These use their considerable experience to help mothers and babies find a more comfortable way of feeding. Ms Garbin and Dr Geddes decided to use ultrasound sonography and a special research protocol to investigate the experience-based advice of lactation consultants.
Dr Geddes is one of the world’s pre-eminent sonographers. She used her skill to revolutionise the world of anatomy in 2005, when she published a paper showing that much that was accepted about the anatomy of the lactating breast since 1840 turned out to be wrong9.
For this work, Dr Geddes developed an innovative way of taking ultrasound movies of infants suckling at their mothers’ breasts. The resulting movies are miracles of imaging, clearly showing the nipple, the baby’s soft and hard palate, and the baby’s tongue moving as well as the milk issuing from the nipple.
When suckling, the baby sucks – it applies a vacuum to the nipple. At the same time, the baby’s high speed sucking after just having latched on turns on the milk ejection reflex. When both these forces work together well, a good, comfortable breastfeed is very likely.
The sucking rhythm of the baby has a distinctive pattern: the strength of its sucking varies between a base and a peak level. And it turns out that there is a range within which these levels should be for breastfeeding to be comfortable – and efficient. Their research shows that uncomfortable, inefficient breastfeeding is often due to these sucking pressures being wildly out of line. Furthermore, by using the ultrasound movies of the moving tongue and nipple, they can see what is going wrong with the feeding process. Sometimes, this is due to a tongue tie: the baby cannot suckle properly. This problem is, thankfully, easily fixed by a little snip.
Using these techniques Dr Geddes and Ms Garbin have been able to plan and deliver effective programmes of care for mothers whose breastfeeding experience had, until then, been a painful, uncertain experience. Their methodology will lead to effective breastfeeding assessment tools. Thanks to this work, improved, science-based care for thousands of suffering babies and mothers can become possible.
Milk synthesis, expression and composition of preterm
mothers
Ching Tat Lai
Pregnancy normally lasts about 40 weeks. But many pregnancies do not reach even the 34 week mark. Babies born at, or even before this early stage of gestation are premature and require significant specialized care in order to survive.
Nutrition is obviously essential. A mother’s breastmilk is recognized as the most suitable nutrition for a preterm baby10. Breastmilk provides much more than nutrition to these fragile infants: essential protective and developmental factors that simply cannot be duplicated by artificial formula milk are found in breastmilk.
9
Anatomy of the lactating human breast redefined with ultrasound imaging - J. Anat.(2005)206:525–534
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Mothers with preterm babies will need to initiate and maintain their lactation by expressing their milk, because their babies are too immature to feed directly at the breast. Establishing regular, productive lactation is crucial and depends in part on the frequency with which the mother expresses. Yet current recommendations range from ‘as often as a term breastfeeding baby’ to ‘every three hours, with no more than a five hour break over night’ to ‘a minimum of five milk expressions per day and a total duration of 100 minutes per day at the breast pump’.
These recommendations are not only very variable, but they are generalized, too. They do not take into account individual differences between mothers. It is thus important to consider the major determinants of milk production and to understand how these vary between individual mothers. The aim: develop recommendations suited to the individual mother so she may maximize milk output – and thus ensure her baby receives what it needs to over these first few difficult weeks of life.
Ching Tat Lai’s findings suggest that blanket recommendations do not benefit everyone. For example, one mother was found to be expressing more milk than another, even though the other mother was expressing more often. These results and others show that there is an intrinsic rate of milk production unique to each mother. Developing ways to determine and diagnose that rhythm is essential and is work we are busy with.
With this information, a mother can determine how much milk she should produce over a given time period. So instead of pumping to the clock, she can pump to a volume and be more secure in the outcome. She can also see when a breastpumping session has not been effective and act accordingly, as several ‘poor’ expression episodes may start to jeopardize her lactation.
Obtaining the milk is but one challenge. The next is to make sure that premature babies receive all the nutritional and developmental components they need. And this is a subject Ching Tat Lai and Professor Hartmann are actively researching.
Linking lactation in the laboratory to real life.
Catherine Garbin
The Lactation Research Team at the University of Western Australia has been conducting research under the direction of Professor Peter Hartmann since 1972. In that time significant advancements in breastfeeding and lactation knowledge have occurred. Through Prof. Hartmann’s efforts we are more understanding of the regulation of milk production and the processes involved in the removal of milk from the breast.
However, this knowledge has not, over the years, been passed down to the one demographic that stands to get the most benefit from it: the mother. This information been restricted to specialised professional journals, and so has remained inaccessible to all but a few doctors, nurses and midwives.
Yet the breastfeeding relationship between mother and baby is bedevilled by problems. Mothers can suffer from stress, self-doubt, conflicting advice in addition to organic issues such as cracked nipples, mastitis or other medical conditions. Babies may not be alert enough, have inappropriate reflexes, refuse the breast, or suffer from nipple confusion. And then there are positioning and attachment issues. To deal with such issues, the medical profession has an increasing hunger for practical lactation knowledge. Traditionally, this has come mostly from experience, with little scientific input. Nurses and midwives were required to use their vast collective experience to tackle and solve problems.
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Working with Ms Garbin, the research team seeks to inform every step of the lactation consultants’ work with its findings. The first such step is to develop an assessment tool to help healthcare workers gauge the mother-baby breastfeeding relationship.
The tool is a checklist of key criteria which research has shown significantly inform the efficiency and comfort of breastfeeding for mother and baby. These criteria are based on clinical observations which healthcare professionals can carry out as part of a breastfeeding check-up. The importance of these clinical observations has been validated with scientific information acquired in the laboratory. The Breastfeeding Assessment Tool is unique in this regard: it compares subjectively acquired information with clinically acquired information on a detailed list of different criteria.
The tool’s 10 different elements were developed by combining the insights from scientific
investigations with the clinical experience of lactation consultants. The science supplements clinical observation with precise, quantitative information related to the critical components of breastfeeding such as milk production, intake and feeding techniques.
The tool is sufficiently detailed so that it may allow practitioners to answer a number of precise
questions that allow an objective evaluation of the breastfeeding relationship. Does it fulfil the mothers’ expectation? Does it fulfil the baby’s needs? Is it comfortable for both? And does baby’s growth meet the curves defined by the World Health Organisation?
While rigorous, the tool is also sufficiently simple so that it could find wide clinical application. It depends on three sensors only: a pressure measurement line taped to the breast, weighing scales, and an ultrasound machine to peek inside baby’s mouth as it is feeding.
With this tool, problem areas can be identified and highlighted for intervention. Just as importantly, the tool allows practitioners to eliminate areas of concern, allowing them to focus their care on areas that have been objectively defined.
Preliminary results show that the tools’ objective measurements of the breastfeeding relationship concur accurately with the clinical evidence gleaned by experienced consultants.
Breastfeeding problems are common. They can range from the very simple to the very complex. In all cases lactation consultants need to assess the situation, plan the care and evaluate progress. Often, however, the root cause of a problem can be elusive. Because it uses scientific evidence, the assessment tool can help identify precise areas of concern, validate clinical practice, and thus ultimately improve care and thus breastfeeding success.
A 160 years of illusion: the anatomy of the lactating breast
Dr Donna Geddes
The current model of the breast, used by surgeons, obstetricians, doctors and midwives around the world, is still based on anatomical dissections published by Sir Astley Cooper in 1840. Professor Peter Hartmann, Dr Donna Geddes and their team, working in collaboration with Medela at the University of Western Australia’s Human Lactation Research Group, investigated the lactating breast using sophisticated ultrasound technology.
The new picture of the anatomy of the breast revealed changes the way the breast should be cared for. And it will help breastfeeding mothers gain a better understanding of the way their breasts work, to the benefit of their health and that of their babies.
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Our understanding of the way in which the breast produces and delivers milk has also changed. Coopers’ model includes so-called lactiferous sinuses, which were believed to store milk. It turns out that these do not, in fact, exist.
In Cooper’s model, fatty tissue is assumed to be evenly distributed throughout the breast. In reality, Dr Ramsay showed, there are three clearly defined areas where fatty tissue is located. Furthermore, there is a greater ratio of glandular tissue to fatty tissue than previously believed. And it is concentrated near the nipple, not evenly distributed in the breast.
At the beginning, many mothers can find breastfeeding difficult, draining or painful. They need the right advice to succeed. The new understanding of the lactating breast’s anatomy will help lactation consultants and midwives give better advice to all breastfeeding mothers.
The fact that an outdated model of the lactating breast has remained unchallenged for 160 years is ample proof that more research is needed into breastfeeding and the lactating breast.
Old model New model
Medela and breastfeeding research
Medela’s contribution to the discoveries mentioned is one of an unusual nature. Medela physically don't do any of the lab work. But Medela helps chart the research course: it is the funding body that agrees to devote significant funds to the pursuit of basic lactation and breastfeeding knowledge.
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About Medela
Medela provides the most technologically advanced breast pumps and breastfeeding accessories to nursing mothers around the world. A long-time champion of breastfeeding, Medela is the only company to develop products based on research by the world’s leading lactation experts. As a result, Medela’s breast pumps are the number one choice of healthcare professionals and facilities worldwide.
Medela has developed an extensive line of products to meet the diverse needs of nursing mothers. These products include hospital-grade, double and single electric and manual personal breastpumps; breastfeeding accessories such as breast care products and specialty feeding devices. Most recently, Medela introduced 2-Phase Expression®, the only research-based breastpump technology that mimics a baby’s nursing rhythm, resulting in faster let-down and milk flow.
Founded in 1961 by Olle Larsson in Zug, Switzerland, Medela continues to grow under the ownership of the Larsson family. Medela serves customers through a worldwide network of distribution partners in more than 90 countries and its 12 subsidiaries in the Benelux countries, Canada, France, Germany, Italy, Japan, Russia, Spain, Sweden and Switzerland, the United Kingdom and the United States.
Contact for media:
Patrick Worms – Aspect PR
Patrick@aspect-pr.be
Tel. +32 (0)2 515 0011
Medela contact:
Medela AG, Corporate Communications
communication@medela.ch
Tel. +41 (0)41 769 51 51
