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Michael W. Woolridge
Abstract
The problems associated with the establishment of lactation can be viewed primarily from the mother's perspective but should also be viewed from that of the caregiver supporting her and the maternity facility providing her with care.
Factors intrinsic to the mother
The first time a mother puts her baby to her breast, she is doing something for which nothing will have adequately prepared her. Childbirth and breastfeeding are comparable in this respect; unfortunately, anticipation of the former may prevent her from giving adequate consideration to the latter, particularly to practical issues. Clinical experience suggests that ensuring that practical issues are correct can be vital to a successful outcome for breastfeeding, yet it rarely proves possible to address them adequately antenatally. The result is that the mother and her newborn, both novices to the process, go through an extremely rapid learning curve that can run completely smoothly or may be fraught with difficulties. Much will depend upon whether the mother encounters problems, and her perseverance and determination in overcoming them. Cultural factors during her upbringing and the expectations of society are likely to influence her persistence, but for individual women little direct influence can probably be exerted over these.
Factors extrinsic to the mother
The pathway to success is not solely determined by factors intrinsic to the mother (or her baby) but also by the quality of care she receives both antenatally in preparation for breastfeeding and post-nasally. Several extrinsic factors can therefore be proposed that are likely to have a beneficial impact on the individual mother's chances of success:
Despite the potential impact of individual-specific factors, it is imperative for the health-care system to offer wellstructured support, ensuring the mother's access to welltrained and motivated staff, to offer all women the best chance of success.
For convenience, the factors leading either to a successful or to an unsuccessful establishment of lactation will be addressed under three broad headings:
Before addressing these issues, I would like to focus on the physiological constraints on the establishment of lactation, looking at the factors that regulate both milk synthesis and effective milk transfer from mother to baby.
How long does it take to establish breastfeeding?
This key question can be addressed by reconsideration of classical physiology. Technically, the new mother must acquire the practical skills for handling her baby and positioning and fixing her baby on the breast. This may take from several days to a few weeks. The more fundamental physiological question is "How long does it take for a mother's milk supply to match her baby's needs?" This question has largely been overlooked, although the evidence has been available for some time.
What triggers the onset of milk production?
At one time the view was current that early and frequent breastfeeding was instrumental in the early establishment of milk supply [1]. The data, however, only support a benefit of frequent suckling: early initiation, per se, has been shown to be without impact [1, 2]. This is because separation and delivery of the placenta, not early suckling, acts as the primary trigger for lactogenesis (the onset of milk production). During pregnancy the breasts have been primed for milk production by a "cocktail" of maternal hormones, some intrinsic to the mother (prolactin, growth hormone, insulin, thyroid hormone) and others originating from the placenta (oestrogen, progesterone, placental lactogen, chorionic gonadotrophin). At birth the placenta is delivered, thus removing a significant source of the steroid hormones (oestrogen and progesterone) that have blocked the action of circulating prolactin upon breast tissue. Lactogenesis then begins, and measurable increases in milk output are detected between 30 and 72 hours after delivery [3, 4]. It is important to appreciate this fact, as retained placental products can be one of the few physiological constraints on the establishment of milk production. Any remaining placental tissue can secrete sufficient steroid hormones and thus continue to suppress the onset of milk synthesis [5].
Variability in lactogenesis
There are dramatic differences between women in both the initial changes in the rate of milk synthesis and the initial level of milk production. There can be a fivefold difference in the initial level of milk output, with infant intakes of between 200 and 900 g/24 hours on the fifth day post-partum [6]. This initial level is unrelated to birthweight; only at four to six weeks of age does infant weight predict intake [79]. Thus, production rates more likely reflect intrinsic variability between women. Physiological factors likely to affect this include variation in the amount of secretory tissue, in circulating hormone levels, and in the sensitivity of response to these hormones, a function of the hormone receptors associated with the secretory tissue.
One implication, however, is that milk production (triggered by placental delivery) is established without clear reference to the baby's size; it is only as a result of the interplay between the mother and her infant that the broad limits on milk output become refined to match the baby's needs. This, in effect, is a "calibration" process, which will involve upregulation of milk supply in the majority of women, whose initial milk output is low, but occasionally down-regulation of supply in women for whom it is initially excessive.
The crucial point is that breastmilk production (supply), which has been initiated "blind," must be progressively fine-tuned (calibrated) to meet the baby's needs (demand). If during this time the baby were offered calories from another source (for example, artificial formula), the blunting of appetite so caused might lead the mother's breasts to underestimate her baby's true needs, with the resultant danger that milk output might be calibrated at an inappropriately low level.
There is clinical evidence (personal observation, author's clinic) that in some women this process of down-regulation may be irreversible. So, if milk output fails to be optimized in the early weeks because of poor management, or if appetite is depressed because of competing calories from an alternative source, then once milk output has been set below the baby's overall needs, it may not be possible to reverse the process. For this reason, the avoidance of complementary milk feedings or "topup" bottles of formula is essential, as they are highly likely to interfere with the establishment of an adequate milk supply.
They can have a further non-physiological effect by undermining the mother's confidence in her milk supply, causing her to feed less frequently. In addition, an artificial bottle teat can represent a gratifying oral stimulus, in simple tactile terms, causing the infant to shift its preference from the breast to the bottle teat (this is discussed at greater length below). Pacifiers and nipple shields can pose a similar threat to the successful establishment of breastfeeding.
How long does this calibration process take?
Published data indicate that milk production continues to rise from birth to around four to six weeks, at which point it tends to reach a plateau [3]. A recent study has placed the population average for peak milk output at just short of five weeks [10], although this underplays the considerable variation that exists between women (five days and six months were the most discrepant points in a small sample of 30 women [6].
Nonetheless, evidence from a compilation of data (cross-sectional) from 16 studies of exclusively breastfed infants [3] indicates that milk output rises sharply until four to six weeks, then levels off at an average of 750 g/day for a singleton. (If a mother has twins, her milk output will continue to climb beyond 750 g/day to around 1,500 g/day, indicating that there is no absolute constraint on an individual woman's milk output, simply that 750 g/day represents the normal level at which milk output stabilizes for a singleton.) When the introduction of weaning foods is delayed, milk output is held at this level for weeks or months [11], until the introduction of solids causes fewer breastfeedings to be offered and milk supply to decline. In many cultures, however, weaning foods are introduced early. In Thailand, for instance, they are invariably introduced by one month of age. In such circumstances, there is a suggestion that they compete calorically with breastmilk, driving milk output down, rather than truly supplementing intake [10].
Factors affecting the establishment of lactation
Cultural Influences on breastfeeding
Breastfeeding fails far more commonly for cultural reasons than for biological reasons. There are few physiological constraints on a successful outcome for breastfeeding. In contrast, the wealth of factors impacting upon the individual woman from family, friends, health-care workers, and the world at large exerts an enormous influence on her. Just as these factors are acknowledged to influence the probability of her initiating breastfeeding, so, too, they are likely to exert an influence over her tendency to continue once she has started.
It is axiomatic to a successful outcome that women should want to breastfeed; women who encounter and overcome breastfeeding problems usually attribute their success to their own perseverance and determination. How do health-care workers inspire in women the desire to breastfeed, and how do they influence their motivation to succeed?
Women's attitudes and beliefs are shaped by their own experience but are also fashioned by cultural pressures, and it may be difficult for health-care workers to exert much influence over these. Nonetheless, epidemiologic research continues to identify the widespread health benefits of breastfeeding to both the mother and her infant [12-14]. If women are to make a truly informed choice on how to feed their infants, then health-care workers have an obligation to provide mothers antenatally with all relevant information about these benefits and about the hazards associated with artificial feeding, irrespective of any pre-existing choice the mother may have.
The role of health-care workers
In the past, a supportive environment for the new mother would have been provided by the extended family, whose members would have undertaken most of the routine tasks that would otherwise fall to the mother. In traditional rural communities of the developing world, cultural taboos on undertaking household tasks may apply for four to six weeks after delivery [15], the time taken for the milk supply to become established. The absence of the extended family in industrialized cultures suggests that motherhood generally is undervalued. In many cultures, particularly those in transition, family ties have been eroded and the extended family has become so fragmented that new parents may have little contact with relatives who would traditionally have provided help and support. Furthermore, in those cultures where bottle-feeding has predominated over the past decades, a vast cultural expertise on breastfeeding has been lost. Under such circumstances, one would hope that health-care workers (midwives and the primary health-care team in the community) would be in a position to make up these deficiencies by providing a collective professional expertise. In practice, however, such an idealized picture does not exist. Little emphasis is given to the management of breastfeeding in professional training, and health-care workers commonly lack both the breadth of knowledge and the core practical skills to enable them to manage lactation effectively. This situation should be rectified as soon as is practicably achievable, by including lactation management in the core training curriculum of every health-care worker whose designated role includes management of the nursing couple (midwives, for example). The emphasis should be on the acquisition of key skills through the mentor-apprentice system, and the combination of knowledge and skills is essential if women are to receive the expert support they need from health care staff.
Perinatal practices that affect the establishment of breastfeeding
It is legitimate to view the factors that either help or hinder the establishment of breastfeeding from the perspective of the maternity facility providing health care. Although largely unpredictable events can shape an individual mother's chances of establishing breastfeeding, there is enormous scope for hospital practices and staff attitudes to impact upon breastfeeding success.
The quality of support in each of these areas can be set through policy formulation and implementation by the maternity facility.
The impact of mafernity care practices
The expectation is of a supportive health-care system, but the reality may be even worse than indicated above. Too often, medical practices in hospital have impeded or hindered the successful establishment of lactation. Historically, separation of the mother and baby immediately after birth was rationalized without empirical justification [16]; such a policy necessitated nurseries for the care of the newborn, which further encouraged the routine giving of supplementary fluids, including formula. Abolishing nurseries as a concept and encouraging the mother to be the primary caretaker with responsibility for her infant through routine "rooming-in" is fundamental to reversing these outmoded practices.
A global campaign, the Baby-Friendly Hospital Initiative, sponsored by international health agencies (WHO and UNICEF) and supported by national governments, is now in place to reverse this situation, by ensuring that hospital practices are designed to protect and promote breastfeeding.
TABLE 1. Ten steps to successful breastfeeding
| 1. Have a
written breastfeeding policy that is routinely
communicated to all health-care staff 2. Train all health-care staff in skills necessary to implement this policy 3. Inform all pregnant women about the benefits and management of breastfeeding 4. Help mothers initiate breastfeeding within half an hour of birth 5. Show mothers how to breastfeed and how to maintain lactation even if they should be separated from their infants 6. Give newborn infants no food or drink other than breastmilk unless medically indicated 7. Practise "rooming-in"-allow mother and baby to remain together 24 hours a day 8. Encourage breastfeeding on demand 9. Give no artificial teats or pacifiers (also called dummies or soothers) to breastfeeding infants 10. Foster the establishment of breastfeeding support groups and refer mothers to them on discharge from the hospital or clinic |
Source: ref. 7.
Under this initiative, hospitals are encouraged to match standards of post-natal care set out in the WHO/UNICEF "Ten Steps to Successful Breastfeeding" (table 1) and to seek external assessment against these criteria. If they are successful in demonstrating compliance with the global criteria, they can be designated as a "Baby-Friendly Hospital," in effect, a global charter mark in recognition that they have made a policy commitment to making the mother and her baby the focus of a supportive, caring environment in which breastfeeding can flourish. The core practices of the Ten Steps are as follows:
Policy formulation.. To minimize the tendency for new mothers to be given conflicting advice, it is vital for all health-care staff to adhere to the same set of practices. The best way to do this is for the maternity facility to establish a clear policy for the management of the new mother and her infant, training all health-care staff to a level where they understand the need to comply with this policy and are able to implement it with confidence. Monitoring staff compliance, breastfeeding intention, and outcome should then become a routine part of the audit cycle. Policies can be refined only if they are strictly implemented, followed by routine monitoring of specific clinical outcomes. Only then can the policy be modified to reduce any adverse outcomes.
Professional training. This requires a commitment to increasing the knowledge and skill base of hospital staff. Eighteen hours of training in lactation management, including at least three hours of supervised clinical practice, is urged by WHO/UNICEF as the minimum necessary for any member of the health care staff (previously untrained in lactation management) who has contact with the breastfeeding mother and her infant. Nonetheless, if routine training (a midwife, for example, might receive prequalification) combined with post-qualification skill development enable nursing staff to overcome routine problems of breastfeeding, these can be deemed both adequate and appropriate, whatever the duration.
Antenatal education. The quality of antenatal education, including whether the proposed method of feeding receives adequate discussion, is highly influential in determining whether women make a truly informed choice on how to feed their infants. It is also to be hoped that all potentially breastfeeding women receive sufficient preparation to avoid or overcome several common initial breastfeeding problems.
Early contact between mother and baby. Early initiation of skin-to-skin contact between the mother and infant, leading spontaneously to the first breastfeeding, is likely to be of fundamental importance in establishing close affectionate ties between them. In the immediate postpartum period, the mother is regarded as passing through a "sensitive period" [18], and the baby shows raised alertness at this time [19]. Although early skin-to-skin contact with the mother will undoubtedly help to reinforce the newborn's ability to seek and locate the breast [19, 20] and to facilitate recognition of the newborn [21, 22], there is little functional need for the altricial human newborn to "imprint" on its mother. For the human infant, it is more important to secure the mother's sustained emotional attachment, so that she continues to provide vital warmth, nourishment, comfort, and protection.
Therefore, early mother-infant contact serves the infant primarily by securing maternal attachment [23] and, as such, it is a biological imperative. Ensuring prolonged highquality contact in the immediate post-partum period, therefore, deserves to be a core practice of intrapartum care, irrespective of how the mother subsequently chooses to feed her infant.
Although there is some empirical support for a maternal sensitive period, there remains the question of whether giving high-quality skin-to-skin contact at a later stage may not also be capable of facilitating the development of emotional attachment, or, conversely, whether subsequent unrewarding or fractured breastfeedings may undo any initial benefits. Of the many studies conducted to evaluate the impact of enhanced early access of the mother to her infant, only one [18] has considered whether there are any deficits if the enhanced contact (45 minutes private, skin-toskin) is provided at a later stage (12 hours after delivery) compared with immediately after delivery. It showed a nonsignificant reduction in affectionate behaviour. A significant graded reduction in affectionate behaviour was observed, compared with a control group of mothers permitted only visual contact with their babies after delivery. Therefore, the evidence is rather slight to contest the possibility that prolonged, high-quality, skin-to-skin contact offered at any subsequent time might be capable of matching some, if not all, of the benefits of early mother-infant contact. If the mother has been deprived of early contact because of intrapartum medication or surgical procedures, high-quality contact should be encouraged with as much enthusiasm at a later stage. Furthermore, professional care should always be available during early breastfeedings and should strive to ensure they are as rewarding and problem-free as possible.
Further key practices. Although practices such as rooming-in and demand feeding may be regarded as essential to breastfeeding success, at a more general level they may be regarded simply as extending the newborn infant the courtesy of being regarded as an individual in its own right, rather than as an imperfectly formed automaton to be directed as we see fit. This change in philosophy in the way we view the human newborn is essential if we are to recognize that the newborn has much right to choice as the mother, although there is an obvious practical constraint on this choice being "informed." If the infants were in a position to make an informed choice on how they would be fed, on health grounds they would undoubtedly choose to be breastfed. It is difficult to see what cultural objections they might raise! So, we must learn to set their rights alongside the mother's and the father's in reaching a decision about the method of feeding. Although it is possible to constrain the infant's pattern of feeding to conform to a Western "idealized" cultural norm- as Pinilla and Birch [24] have shown for night feedings-there is no evidence that this benefits long term habit formation in the child, whereas it may prove detrimental to the infant's emotional development [25].
Avoiding bottles and teats. We have already dealt with the physiological reasons for avoiding unnecessary supplementation and the use of artificial teats and pacifiers. Each of the WHO/UNICEF Ten Steps is research-based, and although this step (step 9) is perhaps the least well supported, it can be defended by arguing both from first principles and from clinical experience. It is important to reemphasize at this point that we are considering events during the critical period of the establishment of lactation. It is acknowledged that different rules may apply during established lactation, when we accept that the occasional offering of bottles for social reasons (preferably of the mother's own expressed breastmilk) is unlikely to disrupt breastfeeding success.
Evidence from a study in Brazil indicates that the use of pacifiers is associated with a shorter duration of breastfeeding [26], as predicted. Clinical experience also suggests that pacifiers can impede the successful establishment of breastfeeding. Although the mechanism is not clear, certain lines of evidence can be considered.
First, ultrasound studies [27, 28] indicate that during suckling the mother's breast distorts and conforms to the internal geometry of the baby's mouth. Milk removal is achieved by the baby's compressing the base of the teatlike shape formed from the breast and nipple between his gums, and expressing milk from the sinuses lying within the "teat bulb" with a peristaltic wavelike action of the tongue. On a bottle teat, the infant attempts to achieve the same action, but because the artificial teat is more rigid, there is. instead, a tendency for the soft tissues of the baby's mouth to deform to accommodate to the geometry of the teat. Expressing milk from the teat bulb may be resisted by the less compliant material from which the artificial teat is constructed, with the result that the baby adapts by a shift towards extracting milk more by suction than by peristaltic expression. If the baby develops a reliance on one method of milk extraction over the other, he may not adapt well when offered both breast and bottle or when shifting between the two. To date, no specific carryover effect has been scientifically demonstrated; it has only been inferred from clinical observation.
Additionally, artificial teats may constitute a "supernormal" sign stimulus [29, 30], causing greater tactile stimulation of the baby's mouth than the more compliant breast. Whereas the breast naturally retracts elastically, the artificial teat remains in place, requiring little effort from the baby to hold it in his mouth. The supernormal stimulus, represented by the artificial teat, can compete for attention with the natural stimulus of the breast, and the baby, if exposed to it at an early stage, may be unable to ignore it. The outcome is that the baby may develop a preference for the artificial over the natural (nipple shields can be comparable in this respect). The term nipple confusion has been coined for the behaviour of the baby who refuses the breast in favour of the bottle or pacifier, but such a term may be insufficiently descriptive. The term acquired teat preference may be more accurate and would still embrace the established breastfeeder who refuses the bottle.
Another possibility is that bottle-feeding bypasses the triggering of the baby's natural adaptive reflexes for feeding and the maturation of the natural repertoire of responses necessitated by breastfeeding (rooting, gaping, drawing elastic breast tissue into the mouth, and suckling) [31]. There may also be a critical window during which the infant's natural response repertoire matures, so that time spent sucking on an artificial teat may represent both a lost opportunity and enhancement of an aberrant response repertoire.
Finally, the excessive use of soothers can mean that the baby is put to the breast either too infrequently or for too short a time, with the result that the baby does not secure sufficient nutrition. Not only can this adversely affect the infant's nutritional status, it will also disrupt the mechanism of supply and demand. At older ages, we have seen infants who are growing inadequately or are failing to thrive simply because pacifiers have been introduced. This appears to be due largely to the net reduction in suckling time and its effect on both immediate intake and future supply, which is only reversed when the mother makes active efforts to withhold the pacifier.
The use of pacifiers can also cause the earlier return of fertility, resulting in closer child spacing. In many cultures this may have an adverse impact on maternal as well as infant health [14, 32].
Cup-feeding. One way around the problem of giving additional fluids, where they are medically indicated, is to give them by cup or spoon [33]. In many centres, cup-feeding has been successfully reembraced and appears to be associated with a greater success rate for establishing breastfeeding.
A multicentre trial has been initiated in the United Kingdom to formally test such a view.
Individual-specific influences during the establishment of lactation
Practices that can either promote or impede breastfeeding success for the individual mother and her newborn can be broadly grouped into the following categories:
For the individual mother, there may be unexpected predisposing factors that militate against the successful establishment of breastfeeding.
In rare circumstances, the baby may be born with an oral anomaly that will require a specialist's attention, or the nature of the baby's birth (for example, pre-term, small for gestational age, or congenital abnormality) may require separation from the mother for medical care. Although medical services should be able to tackle many of the clinical problems with relative ease, the role of the mother at this time can often be overlooked. The one significant thing the mother may be able to do for her infant under these circumstances is to express her breastmilk, yet too few centres recognize the need to attach equal significance to this non-acute aspect of clinical care.
Excluding such medical crises, however, the baby may be sleepy or lethargic as a result of intrapartum analgesia (as from pethidine) [20] or may be irritable following an instrumental delivery. The resulting behaviour, either a lack of response by the baby or signs of discomfort when the baby is handled, may make it very difficult for the novice mother to handle her baby positively and with confidence, and she may feel her efforts to breastfeed are being rejected. Concern should also be raised over increasing reports that modern epidurals and gastric suctioning, either alone or in combination, adversely affect the initiation of breastfeeding; their impact should be evaluated epidemiologically.
The foetus may have had access to its thumb, fingers, or hand in the womb (often observed during antenatal ultrasound examination) and may have had the opportunity to acquire an artificial sucking style. If the foetus has become used to sucking on a discrete, relatively rigid object for several weeks, the infant may find the elastic, retractile tissue of the nipple and areola less attractive in tactile terms and thus may be reluctant to adapt to sucking at the breast. This theory could be readily evaluated by independent assessment of ultrasound scans and early sucking behaviour.
The main reason for raising this theoretical possibility is that it represents a potential individual-specific predisposing factor. We cannot yet predict which babies will or will not find the offering of artificial teats counter-productive to the establishment of breastfeeding, but simple adherence to the policy recommendation in step 9 of the Ten Steps should avert such a problem. It is explicit that this policy relates to the management of the normal full-term infant and that there are permissible clinical circumstances for departing from it.
Caution should be exercised, however, to protect against two harmful inferences: that because a baby has been observed on ultrasound to be thumbsucking in utero, problems will automatically arise with breastfeeding; or that difficulties of fixing and attachment in the early days are due to antenatal thumbsucking, so that no remedial efforts will be made. Neither of these inferences is defensible. Rather, the issue is raised because awareness of the possibility may help caregivers provide appropriate support rather than leaving the mother on her own to come to terms with an unrewarding infant who refuses to feed from the breast. It may be necessary for this baby to relearn how to suck correctly in the context of breastfeeding, in which case the offering of bottles, pacifiers, or finger foods will only perpetuate the artificial oral preference. A baby's early tendency to refuse the breast will undermine the learning experience for the new mother, whereas acknowledgement of her predicament and the offering of appropriate help and support will be encouraging and empowering.
Successful achievement of the technical aspects of breastfeeding will also be militated against if the mother is given inexpert help in attaching her baby at the breast in the early days [34]. Forcing her baby to the breast, or holding him there against his will, is likely to frustrate the woman's own efforts and can lead to many common complaints. The baby may also find these efforts aversive and develop a behavioural coping strategy that presents itself as breast refusal or rejection; once developed, this behaviour can be very distressing to both mother and infant and is often difficult to reverse.
Finally, research conducted with professional referrals to a clinical support service for breastfeeding women [6] has identified several classes of problems, all of which may be perceived as breastmilk insufficiency. While 98% of professional referrals to the clinical service were for reliable symptoms (for example, inadequate weight gain, unsettled infant behaviour, and sensations of reduced supply), up to 85% of them could be reversed by straightforward practical steps that included:
Four demonstrable causes of insufficiency were identified. Genuine pathophysiologies of milk production represented only 2% of clinical referrals. Another category (5% of referrals) represented physiologically low milk output, while the remaining two (8% of referrals) would normally be regarded as lactation failure of maternal origin, but were in fact acquired conditions owing to suboptimal management of the nursing couple (for more detailed discussion, see ref. 6).
Conclusions
The factors most likely to contribute to a mother's initial success with breastfeeding are support and encouragement provided by health-care workers who are skilled and knowledgeable in managing lactation. These professionals must work within a system that is similarly caring and supportive, the policy of which recognizes the intrinsic rights of both the mother and the baby, allowing them unrestricted access to each other (as would be the case if the mother delivered at home). More proactively, the health care system and its staff should positively encourage those practices that have been shown to have a beneficial impact on the establishment of breastfeeding, while eradicating all practical hindrances. Finally, it is to be hoped that the mother will have a relatively trouble-free breastfeeding experience, or at least that her motivation and persistence with breastfeeding will be sufficient for her to overcome any problems she may encounter. A sensitive and supportive attitude from health-care staff will be highly valued by women and can contribute significantly to their success by boosting their confidence in their ability to breastfeed.
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