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Dr. Valdés
I have a question regarding the group of women with an irreversible decline in milk output. You can use lactation in adopted mothers as a comparison. It takes longer, and the production doesn't increase as in the first month. It steadily increases throughout the first six months. Why doesn't that happen in a biological mother?
Dr. Woolridge
Our finding is disconcerting, especially when one hears about grandmothers in Africa who are able to re-establish lactation simply through suckling. Some of our interventions to boost these mothers' supplies have been quite aggressive, to see if there was any way of improving output. We would not diagnose the mothers who responded either to increased suckling or to pharmacotherapy. Where there has been substantial down-regulation, it is often difficult to shift back up. Where there has been up-regulation from birth, the potential to carry on up-regulation is retained. Downregulation, if it is excessive, can be a harmful process. Clearly there are other factors, particularly psychosocial factors in women in industrialized countries, that seem to exert a block over and above the motivation to feed. But in physiological terms, this down-regulation could be a critical factor.
Dr. Rasmussen
I am wondering if any of the babies in what you call the behavioural category, contented failure to thrive, are the ones who were rejecting the breast. Is there any indication that they are responding to the taste of the milk? That is, are mothers eating things that the infants are allergic to or just don't prefer?
Dr. Woolridge
There is no evidence of anything long-term. Certainly there is evidence that the baby will refuse or reject the breast for a brief period, either with the return of the menstrual cycle or from a particular food that the mother includes in her diet. But we haven't seen any long-term cases of breast refusal. I will cite two anecdotes, however. One is a mother who had a severe case of thrush, and she had been given a whole set of pharmacological preparations by her general practitioner. She was putting Timodene, which is for athlete's foot, on her nipples, and the baby was going to the breast but pulling back. She also smoked, and we weren't sure if it was the taste of the nicotine or tar products in her milk. While chatting with her, I squeezed some of this Timodene out onto my finger and tasted it, and it was quite revolting. Clearly, the Timodene was responsible for this baby's reluctance to go to the breast, and that had been going on for eight weeks.
The next example is also quite disconcerting. Recently we saw two babies whose first breastfeedings after delivery had been interrupted to give oral vitamin K. The babies grimaced at being given the vitamin and then refused to breastfeed for the next five days. Now, if you want to teach a baby what is harmful and bad, you give it a feeding and then follow it with a distasteful flavour, a perfect case of one-trial learning. You have to be very careful about when oral preparations are given to the baby, and not give them in association with the first or subsequent breastfeedings.
Dr. Prentice
I wish to continue with the discussion about irreversibility, because certainly in our Gambian experience it is difficult to see how that fits in. Certainly, we see women whose breastmilk volume goes way down in the wet season, possibly because they have become very anorexic with various infections. Then their breastmilk volume will come back up again, will double, and they will be well past the six weeks of lactation at that stage.
Dr. Woolridge
If one accepts that the calibration process takes four to six weeks, the results of down-regulation may differ if the weaning process invades that critical period or comes after it.
Dr. Prentice
What we see is at a later stage. This makes me wonder about the underlying physiology: for example, the role of the number of lactation cells, and what affects their longevity. Are we observing down-regulation? Is the process truly irreversible? What proportion of your subjects producing less than 450 ml of milk were in the irreversible group? Could those you were calling lazy children get used to being down-regulated? Would those mothers respond by increasing milk volume?
Dr. Woolridge
There is some overlap between the groups in about 4% of the clinical population. So I am not suggesting that we should suddenly recalibrate our views, but it is a possibility to be aware of; that is, the process of down-regulation can create clinical dilemmas.
Dr. Victora
I have a question about one of the Ten Steps to Successful Breastfeeding, which relates to the use of pacifiers or dummies. We looked into the literature a couple of years ago and found virtually nothing. Since then, we have done a couple of studies in Brazil that showed that children who had a pacifier introduced in the first month of life were three times more likely to be weaned in the subsequent three to four months than children who were not using a pacifier. The magnitude of this effect was about as large as that of introducing a bottle with artificial milk, so we were quite impressed by our finding. Obviously, we can't know whether this is a cause-effect association, or if pacifier introduction is a maternal strategy for weaning the child. I wonder if you have any data on that, and also if you could let us know if you have had any success in the United Kingdom in preventing mothers from introducing the pacifier?
Dr. Woolridge
We did try to discourage the use of pacifiers up to the time Ed Mitchell found that pacifiers might be protective against sudden infant death syndrome. We are still quite anxious to find out what the explanation for that particular finding is. It is an area where there is huge reluctance, as many women in the United Kingdom use pacifiers quite extensively. Here is one scenario of how these behavioural problems come about. Let's say you have a baby who has had access to his thumb or fist in utero and has become used to sucking on a small, rigid, discrete object. Suddenly the object is no longer available. The baby is encouraged to go the breast, but it doesn't find the breast as physically discrete in terms of its tactile qualities. The baby initially refuses the breast, but the midwife is rather heavy-handed and insists that the baby go to the breast. The baby starts to fight and refuses the breast, and after about three days of this, someone eventually gives in and gives the baby a bottle. The baby thinks, "Wonderful, this is what I have been missing out on," as this is closer to the thing that the baby has been used to. There is some evidence in some babies that, if you like, some antenatal preconditioning changes their expectation of what they should get afterwards. I will show you one last slide. There is much talk about "nipple confusion," which is an expression I don't like. Having trained as a zoologist, I thought I would bring you a piece of Dutch ethology. This is a slide showing how you can fool an oystercatcher into incubating the wrong clutch of eggs. If you give it a clutch of eggs that is larger than its normal clutch, it will incubate those in preference to its own clutch. If you give it a football that is painted to look like its eggs, it will try to incubate that. This is what is called a supernormal stimulus. It's so good at switching on the animal that it can't be refused. Nature didn't expect scientists to come along and paint footballs the colour of eggs. I do think that bottle teats and pacifiers represent supernormal stimuli for the baby. If you like, they stimulate the mouth with a greater tactile strength. For some babies, if breastfeeding is unsatisfactory, they will actually refuse the breast in favour of this more tactile object.
Professor Hanson
You made a comparison between lactating mothers in the United Kingdom and in Thailand. I would like to ask if you could qualify that a bit. Does this mean you are comparing British mothers who are exclusively breastfeeding with mothers in a traditional society, where I am convinced they rarely breastfeed exclusively? For instance, on the Indian subcontinent, a number of traditional foods that are introduced early to the infant are heavily contaminated and may have severe consequences for the infant's future life. A number of severe infections originate from this feeding practice. Once they start other foods, exclusive breastfeeding is rare. Could you speak about this?
Dr. Woolridge
I think the boundaries are very blurred. In Thailand some women initiate weaning foods purely on an experimental basis, introducing very low levels of supplement from, say, one month to three months of age. It's only at about four months that they start to give those weaning foods in substantial amounts, but I agree about the potential contamination. What is intriguing in Thailand is that many of the traditional methods of preparing weaning foods make the food sterile. They will steam rice in a vine leaf, which removes the pathogen load. In the United Kingdom very few mothers actually exclusively breastfeed. The specific recommendation of the Department of Health is to delay the onset of weaning until three months, but when you survey women, you find that most of them have offered their babies something by 10 weeks of age. So in fact there is not quite the discrepancy you might expect between these two cultures.
Professor Hanson
I will not be using the term weaning food in the same way that you do, because from the start of breastfeeding, the whole family-for instance, in Pakistani societies-will participate in feeding the baby and will put all kinds of food in the baby's mouth. This certainly brings the risk of infection and doesn't bring much energy or useful food to them. It is a risk that I think is often disregarded. You would need someone to stay with the family to find this out. What has been called exclusive breastfeeding has often not been.
Dr. Hartmann
I would like to go back to the relationship between socioeconomic class and breastfeeding. The same sort of thing happens in Perth, Australia. In the high socio-economic class about 80% of mothers breastfeed to six months of age. But this is a very recent behaviour. I think the problem is that we haven't successfully reached the lower socioeconomic classes with the breastfeeding message, and that is why breastfeeding rates have reached a plateau.
Dr. Woolridge
I agree, and unfortunately that group is often also very difficult to target in many other respects, such as in relation to the discontinuation of smoking and the way in which they use their financial resources.
Dr. Rasmussen
I want to come back to the comment on the pacifiers and offer you an alternative theory from the maternal perspective. A hungry breastfeeding infant is a vigorous young person who may make the mother's nipples quite sore. The introduction of a pacifier can have what I call the "nipple-saving effect" on breastfeeding continuation in women who might otherwise discontinue. Now in that case you may have women whose breastfeeding is already very adequate, and the pacifier has no effect whatsoever. It may be superior to giving the baby other foods, or it might not be.
Dr. Woolridge
Clinically, our objective when we are counselling women with distressed, unsettled infants is based on the premise that the infant has an appetite-control mechanism and that the most likely regulator of that control is fat intake. We try strategies that maximize the efficiency of milk delivery, so that she can help her baby achieve a state of satiety. You are quite correct that, even when she has an ample supply of milk, if the baby is unsettled, she is likely to resort to a pacifier to find some other way of settling the baby, rather than have her nipple traumatized in the process. Clinically, we focus on the primary target of ensuring delivery of synthesized milk, and then we address colic and other concerns as secondary matters.
Dr. Valdés
One thing I was surprised to see was the differences between economic classes. In the developing countries it is just the other way around: our lower-economic-level mothers nurse much more than those at higher levels. At the same time, we feel that mothers in the lower economic groups are easier to reach. We are much more successful in addressing and changing their behaviours.
Dr. Woolridge
Certainly, there are ways in which it is quite inappropriate to compare an industrial country with Thailand. In the United Kingdom in 1940, the picture is reversed. What is surprising is how difficult we are finding it to target women in the promotion of such a recently acquired practice. Artificial formula was quite appropriately developed as an emergency backup option, but the trouble is that it has become the first choice of too many people.
Dr. Valdés
I have some comments related to pacifier use. I can't understand why the mother would have sore nipples.
Dr. Rasmussen
Poor positioning would do it.
Dr. Valdés
If the mother correctly positions the infant when she breastfeeds, for whatever time, she won't have sore nipples. But what we observe, in waiting rooms for example, are mothers who naturally put the baby to the breast when the baby cries. There, you have short feedings. The mother who uses a pacifier instead of putting the baby to the breast loses an opportunity to feed.
Dr. Pollitt
Just a short comment in connection with this issue of "nipple confusion." We have to remember that sucking on a pacifier is different from sucking on a breast. With the pacifier there is no negative pressure, and the activity of the tongue differs.
Dr. Woolridge
There is also no fluid delivered, so there is no need for phase-locked sucking, swallowing, and breathing, whereas on the breast these different activities have to be phase-locked. On a pacifier breathing is carried out independently from sucking.
Professor Hanson
I'd like to come back to the point of motivating women in poor countries to breastfeed exclusively. We were impressed to find that a motivation campaign in very traditional areas-villages, subslums, and city slums-results in substantial increases in this practice. Even traditional societies can be approached very successfully.