A human milk bank is a service established for collecting, screening, processing, storing and distributing donated human milk.
Donation of breast milk from one woman to an unrelated infant has a long history. Before this century, the infant would have been directly breastfed by the woman who was referred to as a "wet nurse". Rules governing wet nursing have been around since 1800 BC. Wet-nursing itself has had periods throughout history when it has fallen from favor. For example, in the 15th century, wet nursing became very unpopular due to the spread of syphilis.
Human milk banking has had similar peaks and troughs. In the early half of this century, milk banking saw resurgence in popularity, but around the 1970s, this began to change. The first reason for this loss of interest in human milk was the heavy promotion of infant formula, including formulas specially designed for preterm infants. Later, a fear of transmission of viruses, including HIV, in body fluids led to an anxiety about donation of body fluids, including breastmilk.
WHO and UNICEF, made a joint statement in 1980: "Where it is not possible for the biological mother to breast feed, the first alternative, if available, should be the use of human milk from other sources. Human milk banks should be made available in appropriate situations."
Banked human milk is regarded as "the next best" after the biological mother's breast milk. It is used for the treatment of many conditions (mainly in Neonatal Intensive Care Units: NICUs): prematurity, malabsorption, short-gut syndrome, intractable diarrhea, nephrotic syndrome, some congenital anomalies, formula intolerance, failure to thrive, immune deficiencies (IgA).
Studies have found that breast milk has a protective effect against necrotising enterocolitis (NEC). Lucas and Cole found that NEC was 6-10 times more likely to develop in exclusively formula fed infants than in those fed only breast milk, and that NEC was 3 times more likely when formula-only fed infants were compared to those receiving both breast milk and formula. Other studies have demonstrated that formula fed infants had lower IQ scores than infants fed breast milk.
Milk banks vary in their use of banked milk. In some cases, milk is provided for adopted babies or older children with severe food allergies.
In 1988, 72% of the milk dispensed from all the milk banks in the USA was prescribed for infants in neonatal intensive care units, 23% went to babies at home, and 2% was used for pediatric inpatients.
Heat treatment of all donor breast milk.
The Human Milk Banking Association of North America (HMBANA) has exhaustive "Guidelines for the Establishment and Operation of a Human Milk Bank". There are similar guidelines for Britain. Both these countries recommend serological testing every 2 to 6 months of the donor for HIV 1 and 2, HTLV 1 and 2, hepatitis B and C and syphilis.
Another part of screening is a consent form for the woman and her doctor to ensure that neither the donor mother nor her infant will suffer if the mother donates milk.
This varies from milk bank to milk bank. For some centers, hospital patients are the major source of donations, while others will ship milk from interstate from a donor's home. Donors are educated regarding the most hygienic way to express milk. Hand expression is the best method for collection, however some centers will allow certain types of hand pumps to be used. Drip milk (milk that drips from the unused breast during feeding or expressing from the other breast) has a lower caloric content and is more susceptible to contamination, but is acceptable to some centers.
The type of container used for collection also varies according to what is most readily available. Polythene bags are associated with a decrease in the IgA content of milk, while glass is linked to a loss of leucocytes. The current recommendation is that glass is best, but world wide many different types of materials are used. In India steel utensils / containers are used.
103 - 105 - forming units: milk is only used if organisms are skin commensals.
Unless the milk being stored is for a mother's own infant, banked milk is then pooled; a bacterial check is done again here to ensure the pooling process does not lead to contamination. Pooling is usually from 4 to 6 donors and is thought to be beneficial because it averages out the immunological and nutrient content of the milk. The numbers are kept low so that any contamination can theoretically be traced back to its source. In Germany, however, pooling is not used because of the concern regarding contamination.
Most milk banks pasteurize their milk. The old protocol was called "Holder Pasteurization" which meant that milk was heated at 62.5 degrees Celsius for 30 mins, and some centers still use this. New guidelines now recommend 56 degrees Celsius because at this temperature most bacteria and viruses are adequately dealt with, while retaining many of the immunological and nutrition properties of breast milk.
It appears that pasteurized breast milk is as good as raw breast milk at preventing NEC. The milk is again checked for bacterial counts after heat treatment, but no level of growth is accepted.
Some centers analyze each batch of milk for its nutritional content and labeled appropriately. Some centers find it appropriate to try to match the age of the donor's infant to the age of the recipient, but this is not necessary if pooled milk is used.
A review of the literature has found that no banked milk has ever been linked with the transmission of disease, nor has any worker become infected due to the handling of the milk. However, continuing the process of screening and pasteurization is essential in order to maintain this record.
It is possible for the human immunodeficiency virus to be transmitted in breastmilk. However, pasteurization is known to inactivate HIV 1 and 2. HTLV-1 is associated with T-cell leukemia, so it is recommended that women who test positive should not breastfeed; the same recommendations are made for women with HTLV-2.
Hepatitis B is not thought to be transmitted via breast milk, although at risk babies are given hepatitis B immunoglobulin and vaccine to decrease any potential risk. It appears that there is also a low risk of transmission of Hepatitis C via breast milk.
Cytomegalovirus is transmitted via breast milk, although viral shedding varies; less in Colostrum compared with later in breastfeeding. As with HIV, viral shedding peaks during seroconversion, so breastfeeding is not recommended at this time, even though transmission usually does not cause symptomatic disease. Immuno-compromised or very premature infants should be fed on pasteurized milk, or milk donated from a seronegative mother.
Rubella is potentially transmittable in breast milk, but no disease is ever seen. It seems unlikely that herpes is transmitted through breastfeeding, unless there are herpetic breast lesions present.
The American milk bank guidelines give clear recommendations regarding these practical issues. Fresh-raw milk must be stored continually at 4 degrees Celsius for no longer that 72 hours following expression, whereas fresh-frozen milk can be held at 20 degrees Celsius for 12 months. Heat-treated (pasteurized) milk may be stored under the same conditions as fresh milk.
The method of transportation varies from shipping milk in commercial airlines that donate their cargo space, to refrigerated vans (as for blood products) or local volunteers driving their own vehicles.
In France, however, one center lyophilize its milk (a previously frozen liquid is dried under vacuum) increasing its storage duration at room temperature to eighteen months. This technique is not used in other counties for a number of reasons: loss of calcium and phosphorous, cost and possibly inaccurate reconstitution methods.
Most milk banks are "not-for-profit" organizations. Some are actually incorporated into an overall hospital budget, whereas others are completely independent and almost entirely run by volunteers, or private donors as in India.
Some centers pay their donors, for example Norway and France. However, most centers make no payment as it is thought by not paying the donor that you will attract the "right type of donors for the right reasons".
In some cases, the recipients are asked to pay for the donated breast milk mostly to cover the costs of the screening tests. No infant is ever denied donor milk, however, on a financial basis. In England, the milk banks sell the milk at 15 pounds per liter to the Health Authority who then incorporate this into their hospital budget.
Milk banks do not have to cost a lot of money, as shown in India. No cost-benefit analysis has yet been done, but the benefit of reducing the incidence of NEC is substantial compared to the cost of running a milk bank.
The Australian Red Cross Blood Service, Victoria, is considering establishing a human milk bank section within their organization.
The basic infrastructure is already in place within the Blood Bank. The multidisciplinary team who already handles the donated blood is well qualified to handle donated breast milk appropriately. Guidelines for running the milk bank will be established and followed.
Three questions remain. Firstly, will there be enough breastfeeding mothers who will want to donate their milk? The Nursing Mothers' Association of Australia feels there would be a positive response from Australian women.
Secondly, will parents accept donated breast milk for their baby? Pediatricians in NICUs will have the opportunity to educate parents regarding the benefits of breast milk over commercially available formula. Current information will allay fears of viral and bacterial transmission. Thirdly, will doctors prescribe donated breast milk for their patients? A review of the literature has demonstrated no reason for them not to.
It is encouraging to see that milk banks have been running successfully now in many countries: Germany, France, Poland, India, USA, Canada, Norway and Britain. It would seem a logical progression that Australia could also offer this service to ill newborns.
A review of the literature on human milk banking is very positive. The guidelines for North American milk banks (which are followed fairly closely by most other countries) would appear to deal with the concern of disease transmission. On the other hand, presently unknown complications may develop in the future. Therefore, the possible risks must be weighed against the proven benefits of breast milk in each case.
In conclusion, the WHO recommends, "where a baby is unable to receive the biological mother's milk, milk of another mother is next best". In order to ensure a safe supply of breast milk for all infants, regulated milk banking is the safest means of doing this.