1) What's the issue?
Every expectant mother will be aware that the official advice on infant feeding is that 'breast is best'. All other things being equal, breastfeeding has health benefits for a newborn baby over formula feeding (bottle feeding), and a long-running public health campaign promoted breastfeeding over formula feeding on this basis.
Yet most women in the UK do not breastfeed their babies for very long. While about 80% of babies are now breastfed at birth, by three months less than 20% are exclusively breastfed. The official recommendation is that babies are exclusively breastfed – having no infant formula or solid food at all – for six months, but in reality only 1% of babies are exclusively breastfed by this point.
This leaves both mothers and policymakers in a difficult position. Women are told that they are supposed to breastfeed exclusively for their baby's first six months, yet they find that they can't, or don't want to, do this. This can make them feel guilty or anxious about the impact that their 'failure' to breastfeed might have on their child's health and development.
For policymakers, the huge gap between the target and the reality – that 99% of women don't meet that target – is problematic. While many health professionals do want to promote breastfeeding, they do not want new mothers to feel bad about themselves. To set a target that most people will not reach does not make for a credible policy; and in practice, as some midwives have warned, it can create defensiveness and other tensions between mothers and health professionals.
The health benefits of breastfeeding tend to be presented as overwhelming, and imply that formula feeding will cause health problems. But the evidence shows a far less drastic difference between breastfed and formula-fed babies. Below, we review some of the main points that come out of the medical literature comparing breastfed and formula-fed infants.
2) What is meant by 'infant feeding'?
There are a number of ways to feed a newborn baby. In Britain today, these are:
- feeding with formula milk especially developed for infants (formula-feeding or bottle-feeding)
- combining breastfeeding and formula feeding or 'mixed feeding'
- expressing breastmilk by using a special pump and feeding the milk to babies through a bottle.
All of these methods are safe and can work very well for mothers and babies; equally, all have advantages and downsides. The scientific and medical literature indicates that breastmilk is the ideal food for newborn infants – which is why artificial formula milk attempts to replicate, as much as possible, its qualities. However, there is much discussion about exactly how and why 'breast is best', and the degree of short-term and long-term health benefits conferred by breastfeeding.
Meanwhile, research into the social reasons why women breastfeed or formula feed indicate that the relative health benefits of breastfeeding are not the only issues at stake. The pain, discomfort and inconvenience that some mothers experience while breastfeeding, and their desire to share feeding with their partners, all provide an incentive to switch to, or supplement with, formula feeding in the first few months.
3) What are the health benefits of breastfeeding?
The discussion around the health benefits of breastfeeding include both short and long-term advantages. The NHS Choices website suggests breastfed babies have:
- less chance of diarrhoea and vomiting and having to go to hospital as a result;
- fewer chest and ear infections and having to go to hospital as a result;
- less likelihood of becoming obese and therefore developing type 2 diabetes and other illnesses later in life.
The health benefits of breastfeeding tend to be presented in such a way that they seem overwhelming, and give the impression that formula feeding will cause health problems in babies. What the evidence actually shows is a far less drastic difference between breastfed and formula-fed babies.
a) Short-term benefits
The infections which cause the greatest illness in infancy are respiratory, gastrointestinal and ear infections. There is certainly evidence that breastfeeding may reduce the risk of early infections, which may be due to two key reasons.
First, breastmilk contains some of the mother's antibodies that give some protection against infection. Second, there is a risk when making formula milk that equipment will not be properly sterilised, or that the quantity of milk to water will not be properly measured, both of which can lead to diarrhoea.
Diarrhoea, chest and ear infections
According to a comprehensive recent study using data from the Millennium Cohort Study, approximately 12% of healthy, singleton infants in the UK today will have been hospitalised at least once by the time they are 8 months old. Just over 1% of healthy, singleton babies are hospitalised for diarrhoea (gastroenteritis) and just over 3% of babies for Lower Respiratory Tract Infection (chest infection).
The study's authors use a complex calculation to estimate that 53% of hospital admissions for diarrhoea and 27% of admissions for lower respiratory tract infections could have been prevented each month by exclusive breastfeeding. This has the effect of presenting breastfeeding promotion as a public health necessity, and implying that individual babies will be far healthier if they are not formula-fed. But when we look at the actual numbers used in the study, the difference between the effects of feeding method seems far less stark.
For every 2,000 formula-fed babies, just under 4 would be hospitalised for diarrhoea in the first 8 months, compared to 1 per 2,000 among exclusively breastfed babies. For chest infection, 10 per 2,000 formula-fed babies would be hospitalised, compared to 6 per 2,000 who were exclusively breastfed. Curiously those who received both formula and breastmilk (partially breastfed) were at the lowest risk for chest infection.
These figures do suggest that breastfeeding is associated with lower levels of severe diarrhoeal disease or chest infections than formula feeding. But they do not suggest that breastfed babies are never affected by these infections, or that all formula fed babies are at a high level of risk.
A large number of infants – 15,890 – were included in this study. In the first 8 months after births, 4.4% of these infants were hospitalised for diarrhoea or chest infection. This of course means that 15,191 infants (most of whom, in line with the national breastfeeding statistics, would have been formula fed) were not hospitalised for these infections at all.
Another major UK study, 'Breastfeeding and reported morbidity during infancy: findings from the Southampton Women's Survey', also found a similar association between breastfeeding and lower levels of gastrointestinal and respiratory illnesses, and suggested that the protective effect increased the longer a woman breastfed.
However, in common with other studies, this study found no evidence of a protective effect beyond the period of breastfeeding. The study did not find a strong protective effect against ear infections, and noted that other studies have also uncovered inconsistent results in relation to ear infections and feeding methods.
Part of the problem when looking at infections in babies and young children is that many different factors can have an effect. For example, a 1997 study of the increased prevalence of recurrent ear infections among preschool children in the USA analysed the various 'risk factors' for this problem. While breastfeeding did not make much difference, but rather that 'increased prevalence of recurrent otitis media was associated with an increase in the use of child care and a higher prevalence of allergic conditions among children'.
In this study, the explanation for higher rates of infection came from increased contact with other children – indicating the difficulty, in a real life context, of separating the effects of feeding method from other 'risk factors' for transmitting infections.
b) Longer term benefits
Infant feeding is a notoriously difficult area to study, as it is considered unethical to randomise babies to one or other method of feeding, and randomised controlled trials are the 'gold standard' of scientific investigation. Observational studies inevitably involve a large degree of self-selection in the types of mother who breastfeed, and particularly those who breastfeed exclusively for six months or longer.
So for example, in the UK, we know that breastfeeding is most common among mothers who are aged 30 or over, from minority ethnic groups, have left education aged over 18, are in managerial and professional occupations and living in the least deprived areas. This correlation with social class and educational status is important when it comes to assessing long term health and perhaps even more so when it comes to the alleged 'social' benefits of breastfeeding, such as enhanced IQ or 'better behaviour'.
While researchers do try to control for socioeconomic status, the World Health Organization notes the problem of 'residual confounding': that even within the same social group, mothers who breastfeed are likely to be more health conscious than those who do not, which may lead them to promote other 'healthy' habits and activities among their children – attributes which are hard to measure and therefore control for.
There is also an established problem of recall bias (mis-remembering) with breastfeeding studies. For example, a 1990 study by Huttly et al. conducted in Southern Brazil found that 24% of mothers misclassified the duration of breastfeeding, and that misclassification increased with the time elapsed since weaning. The study further found that 'Women who were richer and/or better educated were significantly more likely to report longer durations.'
A series of systematic reviews published by the World Health Organization (WHO) in 2007 and updated in 2013 examined the evidence about a number of long-term effects into adulthood of being breastfed as a child. These included:
Breastfeeding did not seem to protect against total cholesterol levels. In the updated meta-analysis of 2013, 'the beneficial effect of breastfeeding on total blood cholesterol in adulthood was smaller than that estimated by the earlier review'.
The protective effect of breastfeeding, if any, was deemed to be too modest to be of public health significance. Small studies provided evidence that 'clearly overstated the benefits of breastfeeding'.
There are very few high-quality studies in this area, with conflicting results. While the 2013 WHO review found that breastfeeding may have a protective effect against type-2 diabetes, particularly among adolescents, this association seems to be partly accounted for by obesity/overweight, and the analysis notes that '[g]eneralisation from these findings is restricted by the small number of studies and the presence of significant heterogeneity among them'.
Breastfeeding may provide some protection against overweight or obesity but residual confounding cannot be ruled out, 'because in most study settings breastfeeding duration was higher in families where the parents were more educated and had higher income levels'.
Breastfeeding was associated with around an increase, on average, in 2 IQ points, after maternal intelligence was accounted for. WHO researchers believe the association is causal, but say the practical implications of such a modest increase would be open to debate.
One recent US study attempted to address some of the problems indicated above, and particularly those related to selection bias, by comparing the outcomes of siblings who were breastfed or formula fed. The authors studied 11 outcomes, which included obesity, asthma, and various measures of childhood intelligence and behaviour, noting that other studies tend to find that 'children aged 4 to 14 who were breast- as opposed to bottle-fed did significantly better on 10 of the 11 outcomes studied'.
However, by studying siblings born and raised in the same families (and therefore less likely to be affected by differences such as poverty and race), the authors found that 'all but one indicator of child health and wellbeing dramatically decrease and fail to maintain statistical significance'. Indeed, the study found that for some outcomes, 'breastfed children may actually be worse off than children who were not breastfed.' This led the authors to conclude that:
'[M]uch of the beneficial long-term effects typically attributed to breastfeeding, per se, may primarily be due to selection pressures into infant feeding practices along key demographic characteristics such as race and socioeconomic status'.
Cynthia G. Colen, one of the authors, summed up in plain English what the findings mean. 'I'm not saying breast-feeding is not beneficial, especially for boosting nutrition and immunity in newborns,' she said:
'But if we really want to improve maternal and child health in this country, let's also focus on things that can really do that in the long term – like subsidized day care, better maternity leave policies and more employment opportunities for low-income mothers that pay a living wage, for example.'
This speaks to a wider concern, that the focus on breastfeeding may have distracted the attention of policymakers away from other social interventions that could have a far greater impact on children's health and development.
c) Other benefits
In its list of the benefits of breastfeeding, the NHS Choices website claims that breastfeeding 'can build a strong physical and emotional bond between mother and baby' and can give the mother 'a great sense of achievement'. The website also states that breastfeeding 'naturally uses up to 500 calories a day' and that it 'saves money – infant formula, the sterilising equipment and feeding equipment can be costly'. All these things can be true – however, again they need to be put into perspective.
'Free' milk The notion that breastfeeding is 'free' ignores the fact that there are direct costs associated with exclusive breastfeeding for a long period of time. A 2013 study in the Journal of Human Lactation calculated the 'maternal time costs' of exclusive breastfeeding, and found that these mothers 'spent 7 hours extra weekly on milk feeding their infants but 2 hours less feeding solids'. The authors of that study concluded that:
'Exclusive breastfeeding is time intensive, which is economically costly to women. This may contribute to premature weaning for women who are time-stressed, lack household help from family, or cannot afford paid help. Gaining public health benefits of exclusive breastfeeding requires strategies to share maternal lactation costs more widely, such as additional help with housework or caring for children, enhanced leave, and workplace lactation breaks and suitable child care.'
Bonding Many mothers enjoy the emotional and physical experience of breastfeeding. However, this is very different to the claim that breastfeeding helps women to 'bond' more effectively with their baby than if they were formula feeding: a statement that seems to be based largely on a prejudice about the 'kind of mother' who selflessly breastfeeds compared to the 'kind of mother' who selfishly bottle-feeds.
A 2008 review of the literature on 'Breastfeeding and the mother–infant relationship' by Jansen et al. found that the widely-held assumptions about a positive association between breastfeeding and the mother-infant relationship 'are not supported by empirical evidence'.
A 2003 study by Else-Quest et al. also noted that 'little research has investigated the role of feeding method in the development of the maternal bond and the mother-infant relationship'. Their study 'tested two hypotheses – the bonding hypothesis and the good-enough caregiver hypothesis – regarding the association of breastfeeding with maternal bonding and the mother-infant relationship', and found that:
'Although breastfeeding dyads tended to show higher quality relationships at 12 months, bottlefeeding dyads did not display poor quality or precarious relationships. Such results are encouraging for nonmaternal caregivers and mothers who bottlefeed their children.'
The notion of maternal-infant bonding has itself been controversial and contested since the 'discovery' of this phenomenon in the 1970s. Diane Eyer's 1992 book Maternal-Infant Bonding: A Scientific Fiction details at length the methodological flaws within 'bonding' research, while the academic obstetrician William Ray Arney's 1982 book Power and the Profession of Obstetrics has attacked bonding as a 'pseudo-science', which gained ground primarily because it boosted the 'prejudice' that 'women interested in pursuing a life in which children are not the raison d'être of women or their exclusive focus of attention' could damage their children.
A similar objection could be made about the way in which claims about bonding are used to encourage women to breastfeed. There is a presumption that mothers who choose to breastfeed love their babies more, and will therefore develop a better relationship with them.
This is an unfair slight on the majority of women, who end up formula feeding. It also contradicts what experience and common sense tells us: that women able to make a choice about what feeding method best suits them and their baby are surely more likely to be able to relax and enjoy the first few weeks and months than those who are struggling.
d) So what's the balance?
The wealth of literature on the health benefits of breastfeeding versus formula feeding strongly suggests that breastfeeding has a relatively protective effect against certain infections. However, when this effect is quantified, it is appears small. Meanwhile other claims about breastfeeding, such as those related to IQ or behaviour, are so strongly influenced by wider socioeconomic factors that it is very difficult to isolate feeding method as the cause.
While it is legitimate to say that, all other things being equal, breastfeeding is the 'healthier' option, it is not legitimate to overstate claims about the health properties of breastfeeding or to use these as a way to restrict women's choices about how to feed their babies. Nor is it legitimate to deny that there are some very real disadvantages to breastfeeding, which is why most mothers continue to rely on formula feeding in the early months.
4) Why don't women breastfeed?
Some women do not want to breastfeed. They might not want to want to use their bodies for feeding; they might want or need other people, such as the baby's father or grandmother, to feed the baby; they might have seen other women struggle with breastfeeding, or other babies thrive on formula-feeding. As we note above, the fact that breastfeeding has some health benefits does not mean that formula-feeding is bad for babies; and in a context where an alternative to breastfeeding exists, some will choose that alternative.
Many women do want to breastfeed, and four in five start out trying to do so. But breastfeeding does not always work. Some mothers find it painful, unpleasant, or inconvenient. Common effects can include sore or cracked nipples, sore breasts, blocked ducts, mastitis, and thrush. While the official advice is that women suffering from these conditions should persevere with breastfeeding, many women understandably find the pain and discomfort a reason to introduce formula feeding.
Mastitis is a condition that causes a woman's breast tissue to become painful and inflamed, and she may also experience flu-like symptoms such as a high temperature (fever), aches and chills. It affects around 1 in 10 breastfeeding women and usually develops in the first three months after giving birth. Thrush is a fungal infection that is easily spread from mother to baby, and requires treatment with creams or tablets.
Some babies struggle to latch on to the breast or to suck; this may be exacerbated by premature birth, tongue-tie, or if the mother has flat or inverted nipples. It can take time to diagnose and resolve these problems, which can result in hungry babies and anxious mothers.
In extreme cases, babies that struggle to breastfeed can become severely dehydrated. For example, a 2013 study by Oddie et al. over 13 months using the British Paediatric Surveillance Unit found 62 cases of severe neonatal hypernatraemia (dehydration, where sodium levels are very high and fitting can result). Of these 62 cases, 61 mothers had intended to achieve exclusive breast feeding. The authors concluded that:
'Neonatal hypernatraemia at this level, in this population, is strongly associated with weight loss. It occurs almost exclusively after attempts to initiate breast feeding.'
While in the Oddie study, none of the babies appeared to suffer long-term health consequences, feeding problems can have tragic consequences. In 2012, it was reported that the NHS Litigation Authority set aside £235.4 million to settle 60 cases in which hospital staff failed to spot hypoglycaemia (low blood sugar levels) in newborn babies, often caused by feeding problems and, in the most severe cases, resulting in brain damage or death.
Because formula feeds are made up to a particular quantity and given in a bottle, it is easy to tell how much milk a baby is being given, and to increase and reduce quantities as desired. This can be very important where there are concerns that breastfed babies are failing to put on enough weight, and their intake of milk needs more careful monitoring.
Formula feeding has a number of other practical advantages. This is why many parents continue to use this method, despite the aggressive promotion of the benefits of breastfeeding. Bottles can be prepared and given to the baby by anybody, making it easier for parents to share night feeds and to go out without the baby. This means that other adults, such as grandparents, friends or relatives, can provide more practical help and support to new mothers and feel more involved in the baby's care.
5) What are the problems with formula feeding?
Compared to successful breastfeeding, formula feeding can be more labour intensive. It requires supplies of formula milk, thorough cleaning and sterilising of bottles and teats, and preparing feeds. Parents who formula feed do not have a supply of milk 'on tap' and so have to carry bottles around with them.
If formula feeds are made up with too much powder to water, this can result in dehydration; if they are made with not enough powder, babies can go hungry. While it is now possible to buy cartons of ready-made formula, these are expensive and cumbersome when buying in bulk. When equipment is not sterilised properly, gastrointestinal infections can result.
And formula feeding is expensive. Perhaps because of the idea that breastfeeding is always better than formula, there has been no campaign in Britain to reduce the price of formula milk: for example, through the development of generic brands, as has happened in the USA. This is ironic, given that one of the objections to infant formula is that it is big business; arguably, a more open approach, which recognised that most women are likely to use formula milk in their baby's early months, might allow for the development of a more standard and affordable product.
Formula milk remains different from breast milk in one key respect: while breast milk is produced by the individual woman for her individual child and changes in composition and quantity according to the infant, formula is a standard product and cannot precisely replicate all the qualities of human milk. It is true that, as the NHS Choices website puts it, formula milk is 'not a living product so it doesn't have the antibodies, living cells, enzymes or hormones that protect your baby”.
This is why 'breast is best' is such a powerful commonsense assumption. It is also why scientific evidence finds relative health benefits of breastfeeding, such as immunity to infection, which are additional to the nutritional qualities of the milk. However, formula milk is more flexible – and babies more resilient – than they are often given credit for. The types of infant formula available today come quite close to the nutritional qualities of breastmilk, even if they cannot mimic all its other properties.
In parts of the world where there is limited access to clean and/or boiled water, formula feeding can cause major health problems related to infection or dehydration. This is why there has been a long-running campaign, since the 1970s, against the promotion of formula feeding in the developing world. But it is important to note that women in the developing world experience the same problems with breastfeeding as do women in the developed world.
While formula feeding is problematic in developing societies, breastfeeding is not 'perfect' either. It is also important to note that many of the dire consequences of formula feeding in some developing societies cannot simply be mapped on to the developed world, where levels of sanitation and access to boiled water make formula feeding very safe.
6) What has been the impact of breastfeeding promotion?
Exclusive breastfeeding has been officially promoted in Britain for several years now, and much is made of the concurrent rise in breastfeeding rates. The Infant Feeding Survey published in 2012 showed that between 2005 and 2010, the proportion of babies breastfed at birth rose from 76% to 81%; at three months, the number of mothers breastfeeding exclusively rose from 13% to 17%, and at four months, from 7% to 12%. Rates of 'any breastfeeding' also showed a rise, from 48% to 55% at six weeks, and from 25% to 34% at six months.
The first point to note about these figures is that the absolute rates of breastfeeding are still low, and strikingly so given the uncompromising character of the breastfeeding promotion campaign. It is not surprising that four in five women initiate breastfeeding, given that they are all but instructed to do so in hospital. But by six weeks, only half of women are doing any breastfeeding at all, and by three months, fewer than one in five are breastfeeding exclusively.
Most significantly, 99% of women do not meet the government target of exclusive breastfeeding until six months. There is always a problem when policy targets are so out of kilter with people's actual behaviour, and this cannot be resolved through simply 'more of the same' breastfeeding promotion messages.
There is also a growing awareness that the one-sided promotion of breastfeeding can make new mothers feel guilty, upset and angry when they 'fail' to breastfeed for any length of time. In research on 'Mothers' experience of, and attitudes to, using infant formula in the early months', published in 2005, one woman's account expressed how deeply the 'failure' to breastfeed can be experienced:
'I felt like a failure, I felt embarrassed, I felt miserable. I thought everyone was looking at me, and like I constantly had to justify myself. I just went on and on about it [use of formula milk]. I was swamped by it. Looking back I think I was depressed. I feel that I lost the first couple of months of the baby's life really. I didn't enjoy it, and I was very unhappy. I think it was taken away from me.'
This research also highlighted the problem that aggressive breastfeeding promotion can make relationships between women and the health professionals who care for them defensive and fraught. One woman said:
'I never ever at any point felt that any of the midwives were like 'oh that's fine, that's your decision, great, how are you with it'. I mean I did have a midwife once ask me and when I said I just don't like the idea of the breast she goes "well that's not what they're there for, sex, you know, it's for breastfeeding a baby."'
The Department of Health has now taken into account concerns that breastfeeding promotion can lead to women struggling to access advice about formula feeding. In 2012, it issued a new 'Guide to bottle-feeding', which contains basic information on how to make up feeds. This will help women seeking practical information, but it does not tackle the wider sense of stigma that formula-feeding mums experience.
Writing in the Daily Telegraph, Rosie Murray-West described how restrictions on the marketing of formula milk can make parents feel bewildered and 'unempowered': 'We can research the best car seat, the best buggy, and the best weaning foods for our babies, but because we are all supposed to be exclusively breastfeeding, the business of buying and making up baby formula remains a mystery.'
A spirited column by Emily Maclean, a student midwife at King's College London, begins by noting that:
'We live in a rights-based age that generally respects a woman's discretion to decide what she eats during pregnancy, where to give birth, and whether to shave her armpits before she does. Yet when it comes to feeding her baby, there seems less room for manoeuvre.'
Against the 'nasty kind of mud-slinging' that characterises the breast v formula debate, Maclean proposes that 'if a mother has 'weighed up the pros and cons to reach the right decision for her, why make her feel bad?' This, really, is the question for infant feeding policy going forward.
7) What would a sensible policy on infant feeding look like?
The health benefits of breastfeeding over formula feeding are real, but they are more marginal than is often suggested. Modern infant formula provides a safe alternative or complement to breastfeeding, and the majority of women continue to use it, for reasons that are valid and understandable.
In this context, there is a major question about whether there should be an official policy on infant feeding at all. The attempt to enforce exclusive breastfeeding for six months has had a number of negative consequences for women's emotional experiences of caring for their newborn babies and their relationships with health professionals.
Beyond this, there is an important principle of reproductive choice. The official demand that women's breasts should provide the sole means of sustenance for her baby runs counter the idea that women should be able to decide for themselves what to do with their bodies. As such, the promotion of breastfeeding over other safe and nutritious methods of infant feeding is an assault on women's reproductive choice.
Insofar as policy should engage with infant feeding, it is of course the case that women who wish to breastfeed their babies should be supported in doing so. Even with the increase in lactation counsellors and breastfeeding support groups, women who are struggling to breastfeed cannot always access the advice and assistance that they need, and can end up formula feeding even if they do not want to.
One regrettable impact of the message that 'breast is best' and 'anyone can do it' is that this often glosses over the problems that can be experienced with breastfeeding, and does not take account of the services that might be necessary, particularly when women are discharged from hospital relatively quickly after birth.
Women who want to formula feed their babies, or who end up doing so because of difficulties with breastfeeding, should also be supported in their decision and given the advice that they want and need. This does not simply mean being taught to make up a bottle of milk: it should include sympathetic discussion about difficulties in the process of feeding, or problems such as colic or constipation. While individual health visitors and midwives often take a flexible approach to the mother and baby with whom they are dealing, they can still feel under pressure to encourage a mother to persevere with breastfeeding against her wishes, or when she or the baby seem to be struggling.
Policy needs to reflect the flexibility and open-mindedness that health professionals need when engaging with new mothers, and focus less on increased breastfeeding rates than the truly optimal outcome: thriving infants.