Breast or artificial formula milk feeds? The controversy faced by HIV-positive women.

Introduction

This paper is written in an attempt to convey the ethical dilemmas faced by healthcare professionals who work with women and are involved in making decisions around HIV and breastfeeding, because: in reality, there is no 'one size fits all' policy[1]. There is a large and growing body of available evidence on this very emotive subject, yet Sachs puts forward that much of the literature appears to be tinged by people's personal and very strong views [2]. This makes it difficult for professionals to sift the chaff from the wheat.

Recent research demonstrates that the choice of feeding method for HIV-positive women is not clear-cut [1,3-12]. Overall, there is a presumption that a suitable substitute for breast milk exists in the United Kingdom and it has been decided that formula milk feeding is the only safe choice for HIV-positive women [10-12]. More recently this conjecture has been challenged [1] and some argue that the debate needs to be re-visited [2]. Sachs suggests that the perceptions drawn out within the discussions about HIV and breastfeeding 'illuminate our attitudes, throwing into stark relief the generally low cultural value of breastfeeding in the West' [2, p. 189].

UK health professionals continue to be left with a challenging dilemma: whilst it is desirable to lower the risks of mother-to-infant transmission of HIV, they must also be able to provide information on competing risks. The Department of Health Guidance [10] did not state that women should not breastfeed but instead suggested that most HIV-positive women would avoid breastfeeding. If women 'insisted' on breastfeeding then health professionals were directed to advise them about early cessation and good breastfeeding practices that would reduce risks.

More recent advice from the Department of Health policy [12] states 'professionals should promote infant formula feeding' with 'avoidance of breastfeeding to prevent transmission of HIV', and it is clear that this recommendation is the one chosen and adhered to in current, everyday practice. However, the document also recognises that the guidance given is for women living in the United Kingdom. If the healthcare professional is informed that a mother may move somewhere where safe infant formula feeding is unavailable, different considerations will apply and healthcare professionals will need to be able to discuss different options and competing risks on an individual basis [12].

Influencing healthcare professionals

The challenge and balance that healthcare professionals must strike is in understanding the relative risk associated with HIV transmission through breastfeeding, while supporting the pregnant woman in 'informed decision-making' and 'choice' on whether or not to breastfeed. However, in fairness some healthcare professionals may not have the right skills or even the knowledge to effectively counsel HIV-positive women [2,13] on matters that are related to feeding or even to HIV testing. The Nursing and Midwifery Council is clear:

   Midwives should work in partnership with the woman and her family.
   Should enable the woman to make decisions about her care based on
   her individual needs, by discussing matters fully with her and
   should respect the woman's right to refuse any advice given [14, p.
   17].

There exist then, both ethical and moral obligations to 'safeguard' babies from vertical transmission of HIV. Furthermore, as Kent [15] suggests, linked to this duty is a human rights issue: a family should be provided with information on all available feeding methods and the risks associated with each. Only the members of the family know the cultural context of their own situation and they must be empowered to choose what is right for themselves and also for their babies.

Transmission risks

UK policy has stressed the importance of HIV screening with early responsive interventions, setting a target of 90% of mothers to be tested for HIV by 2002 [16]. HIV is transmitted through body fluids: primarily blood, semen, vaginal fluids and breast-milk. Transmission to babies can occur in utero, at the time of birth, and postnatally, whilst the baby is being breastfed.

The Department of Health suggests that in the UK and equivalent settings, the risk of HIV transmission through breastfeeding for women on highly active antiretroviral therapy (HAART) has not been quantified [10]. Whilst the risk is likely to be low if plasma viral load is undetectable, the potential for proviral DNA to transmit infection, resistance due to poor drug penetration into breast-milk and prolonged exposure of the infant to antiretroviral drugs, all need to be considered in the balance of risks [12].

The European Collaborative Study [17] proposed that the vertical transmission of HIV in this country without intervention is thought to be 15-20%. In women with recent infection the risks were found to be higher, with UNAIDS reporting a risk of 29% [7]. Lindegren et al. [18] suggest that the risk of HIV transmission can be reduced to between 1% and 2% by taking the following measures:

* Treating the mother with antiretroviral drugs during pregnancy.

* Treating the newborn with antiretroviral drugs.

* Elective caesarean section (see also page 6 of this issue).

* Not breastfeeding.

Transmission associated with breastfeeding

HIV was detected in breast-milk samples in the 1990s. However, the implication of virus in breast-milk is not well understood and the association between viral levels in maternal plasma and breast-milk is not clear [19]. Infection by breastfeeding may occur through cell-free virus in breast-milk or HIV-infected cells. If the latter is true, colostrum might be more infectious as it is richer in macrophages [20]; however, the Department of Health contests this stating it is inaccurate and that there is no current evidence that colostrum poses any greater or lesser risk than later milk [10].

Breast milk contains immunoglobulins, in particular immunoglobulin A (IgA) [21]. Van-De-Perre [22] suggested that these immunoglobulins may protect an infant's immature gut mucosal surface from the invading virus, rather like an antiseptic paint, and that this effect may prove valuable in reducing both morbidity and mortality associated with the disease.

Dunn et al. [23] conducted a meta-analysis of data and calculated the risks of transmission through breastfeeding. They estimated that 14% of HIV-positive women who breastfeed would transmit HIV to their baby via this route. The calculated risk was over and above any transmission in utero or at birth. Studies also indicate a higher level of transmission during seroconversion or where there is a low CD4+ count at the time of birth [19]. The risk of transmission via breastfeeding ranges from 5% to 20% [19].

More recently the Breastfeeding and HIV International Transmission Survey Group [24] analysed data from nine trials on 4085 breastfed children that were testing effects of vitamin therapy and antiretroviral drugs on transmission. The Group calculated that the risk of transmission remained roughly constant during the period of breastfeeding and was around 4% for every 6 months of breastfeeding [1,24]. But as Sachs [2] eloquently states 'it is easy to overlook one vital point: the majority of women who breastfeed do not transmit HIV to their babies through breastfeeding' (p. 168). Thus, stopping women breastfeeding may limit the main postnatal route of transmission but it will not address transmission during pregnancy and/or birth and this area needs equal consideration.

Mixed-feeding

Most women end up mixed-feeding their babies early in their life, usually within the first few weeks or months. Mixed-feeding (which is defined as feeding breast milk and other foods or liquids) significantly increases the risk of HIV transmission because it combines the risk of gastrointestinal and other infections, often considered risks of using infant formula or modified animal milks, with the risks of transmission due to breastfeeding [21]. One could therefore assume from current evidence that in developing countries replacement feeding is not really a safe option and may even cause risk, particularly if healthcare professionals can not fully inform women of the evidence of 'competing' risks [25]. It is important to share information that highlights that the safest option is either exclusive breastfeeding or exclusive replacement feeding, whilst mixed feeding is most definitely unsafe.

The latest evidence from Durban, South Africa, has brought to public attention that in developing countries the good intentions of government agencies and non-governmental agencies, for example, UNICEF, have fallen by the wayside. Even when replacement feeds are provided free, morbidity rates have increased. These have not just been associated with breastfeeding but rather with illnesses associated with replacement feeding. Poor, uneducated women and their families are unlikely to be able to safely reconstitute formula milks. Often there is no access to clean water, refrigerators, fuel to boil water, bottles, soap to wash hands or even to money. In such dire situations it is likely that their babies will not die from HIV but from diarrhoea or even malnutrition [21].

Current evidence shows that in developing countries, where babies are exclusively breastfed there is a reduced rate of infection, in particular for gastrointestinal infection [26]. It is likely that the infant's gut mucosal surface is also the point of entry for HIV, thus gut integrity may be a crucial factor in HIV transmission rates. Vnuk [27] suggests that 'even one bottle of formula milk can reduce the acidity within the baby's stomach' and as HIV is an acid labile virus, reduction in stomach acidity might further enhance the survival of any maternal HIV-1-infected cells.

Exclusive breastfeeding

Exclusive breast-feeding is recommended for the first 6 months of an infant's life, as it takes this length of time for the infant's immune system and gut integrity to become complete [26,28]. Exclusive breastfeeding is defined as:

   The infant had received only breast milk from his/her mother or a
   wet nurse, or expressed breastmilk, and no other liquids or solids,
   with the exception of drops or syrups consisting of vitamins,
   mineral supplements or medicines'. [28, p. 2]

Coutsoudis [1] followed a cohort of mothers and babies up to 15 months of age; mothers had made an informed choice to either breast- or formula milk feed. Those that chose to breastfeed were given information on exclusive breastfeeding. The findings of this study were to challenge prior beliefs, for it was found that babies who were exclusively breastfed to 3 months and those that were never breastfed had similar rates of HIV transmission, while babies that were mixed-fed showed higher rates. The findings at 15 months illustrated that rates of HIV infection in babies exclusively breastfed to 4 months and babies never breastfed to 4 months continued to remain similar up to 6 months of age [5]. However, no baby in the study was exclusively breastfed up to 6 months, thus rates of transmission continued to increase above that of the never-breastfed group. Coutsoudis states [in 30] 'our latest findings corroborate our earlier observations that mixed breastmilk and formula milk feeding is an important risk factor in MTCT, and that exclusive breastfeeding in the first six months of life cuts transmission by at least fifty percent'.

Recent findings from Zimbabwe [30] show that mixed feeding more than doubles the rate of transmission of HIV through breastfeeding in the first 6 months of life. The findings also show a dose-related effect. Predominantly breastfed infants (given breast-milk and non-milk liquids) experienced lower rates of transmission than mixed-fed infants, but higher rates than exclusively breastfed infants. Furthermore the study showed that two-thirds of postnatal transmissions occur after 6 months.

Kent [31] analysed some of the studies that have been carried out. He implies that analysis is difficult for healthcare professionals as the estimated rates of transmission are so variable. For example, some have estimated that breastfeeding by HIV-positive women increases risk of infection by about 14% [23]. Others suggest 'the incremental risk of transmitting HIV infection to the breastfeeding infant ranges from 3% to 12% in various African populations' [32]. One study estimated that only about 1% of infected infants is infected through breastfeeding [33]. Kent argues that if the transmission through all three pathways (in utero, at birth and breastfeeding) is between 15% and 30% this means, at most, about 0.3% of the infants of HIV-positive mothers are at risk of infection through breastfeeding. He puts forwards that in the US, it has been estimated that where there is transmission of the virus to the infant, 70-75% of cases occur during delivery, and 25-30% occur in utero [34]. He concludes this suggests that only about 5% of the cases of infection occur as a result of breastfeeding.

Safe feeding options for HIV-infected women

It is recommended that in exceptional circumstances, and after seeking expert professional advice on reducing risks of HIV transmission through breastfeeding, a highly motivated and informed mother might be assisted to breastfeed [12, p. 14]. However, the woman should be advised that any breastfeeding carries some risk and an individual risk assessment should be carried out. Where mothers choose to breastfeed they should do so exclusively and should be advised:

* To adhere to the antiretroviral drug therapy for both mother and child.

* Breastfeed exclusively and do not use any supplements of formula milk or other drinks.

* Breastfeed for a short period of time only, to rapidly wean from the breast between 4 and 6 months, thus providing the benefits of breastfeeding with a minimal risk of HIV transmission.

* To seek skilled help with positioning and attachment of the baby to the breast.

Furthermore in order to minimise risks Embree et al. [35] suggests that mothers are informed of variables that make breastfeeding more 'risky':

* Seroconversion during the breastfeeding period.

* Continuing to breastfeed with sub-clinical mastitis, thrush, a cracked or bleeding nipple or a breast abscess.

* Breastfeeding with a high viral load or low CD4 count.

* A high viral load in the breast-milk itself.

* Breastfeeding beyond 6 months

* Mixed feeding.

It is clear that a knowledgeable health professional must be made available to support HIV-positive women with the challenges of exclusive breastfeeding.

Heat-treating or pasteurisation of breast milk

A safe and feasible option would be to heat treat, boil or to even pasteurise hand-expressed, or expressed breast milk. A personal pasteurisation unit costs approximately 50 [pounds sterling] in the UK. HIV is destroyed by heat, and while the treated milk will provide a reduced level of immune system protection, it is still more physiologically suitable for a baby than formula milks that lack these protective elements [8,9,25]. Women may want to give donor milk to their babies rather than formula milks and the re-establishment of donor milk banks in the UK may make this a feasible option in the future. In some cultures it may even be considered acceptable for the baby to be fed by an HIV-screened wet-nurse.

Conclusion

This paper was written in an attempt to highlight the uncertainties that surround HIV and infant feeding. Choices for HIV-positive women in this area within the UK are limited because of the insecurities and fears that exist about transmission rates linked to breastfeeding. However, in the UK, there is access to safe water supplies and to formula milks. The Department of Health recommendation in the UK is clear: 'women who are infected with HIV should avoid breastfeeding to prevent transmission' [12].

On the other hand, in developing countries the move towards abandoning breastfeeding altogether has halted and more recent research has led to an endorsement of either exclusive formula-milk feeding or exclusive breastfeeding with appropriate and timely professional support. UK healthcare professionals, in advising women on breastfeeding, need to consider whether they may migrate back to developing countries and give advice as to what is considered 'safe' or 'unsafe', accordingly.

The difficulty that further compounds professional advice is that within the UK not many women exclusively breastfeed nor do they understand what this term means. Healthcare professionals often find themselves in a similar predicament as many have lived and have been working in predominantly bottle-feeding cultures. Furthermore there continues to remain a need for well-designed research to resolve the major issues that surround this ongoing debate.

References

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Valerie Finigan

Infant Feeding Coordinator, Pennine Acute NHS Hospitals Trust; Royal Oldham Hospital 

Correspondence: Valerie Finigan, Pennine Acute NHS Hospitals Trust: Royal Oldham Hospital, Rochdale Road, Oldham, OL1 2H. (Email: [e-mail])