Are there risks to using donor milk?

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There are always risks associated with feeding a baby anything other than his or her own parent’s healthy breastmilk via direct nursing.1 When considering (private) donor milk, parents are balancing the benefits of optimal nutrition and immunity against the risk of disease transmission. Some argue that even after donors are screened, a small amount of pathogens can still remain in the milk and that therefore raw donor milk is never safe.2 However, when considering pasteurized milk, there are also risks that need to be evaluated, and in situations where donor milk has been pasteurized, pathogens can (re-) contaminate milk (see below).

Informed milk sharing3
To our knowledge, there are no documented cases of disease transmission or bacterial infection associated with informed milk sharing at this point.

Milk sharing is also not considered to be a pressing public health risk according to Dr. Chessa Lutter, Regional Advisor on Food and Nutrition for the Pan American Health Association (Regional Office of the WHO) on ‘The Current.’ From the interview:

Q: “Is Eats [on] Feets (sic) safe in the opinion of the World Health Organization? Are they a credible alternative?”
A: “We don’t have a position on this. We focus our efforts on what we consider are the most pressing public health concerns. This has not made it to the top of the list. What I would like to share…”

Dr. Chessa Lutter goes on to describe a pediatrician’s positive donor breastmilk experience.

For a podcast of this interview, please go here.

There may be concern regarding the spread of infectious diseases through breastmilk, in particular HIV. The CDC states: “HIV and other serious infectious diseases can be transmitted through breast milk. However, the risk of infection from a single bottle of breast milk, even if the mother is HIV positive, is extremely small. For women who do not have HIV or other serious infectious diseases, there is little risk to the child who receives her breast milk.” Please see ‘How can breastmilk be pasteurized at home?’ for more information on mitigating the risk of exposure to HIV and other pathogens.

Risk from handling
Some of the risks associated with donor milk are caused by the method used to feed the milk to the baby.4 There have been documented cases in hospitals where newborns developed bacterial infections after receiving milk obtained from milk banks and delivered via feeding tubes or artificial nipples. For instance, “one outbreak of F. meningosepticum was not from milk, but was located on milk bottle stoppers and ‘cleaned’ teats, as well as the ward environment.” La Trobe Table #5 identifies four related deaths as a result of contaminated breastmilk in hospitals. Some of these infections appear to have been associated with a single donor, which indicates that there was some cross contamination that occurred with that particular batch of donor milk. The infections linked to contaminated breastmilk were generally caused by normal bacteria that live on human skin and are by definition not isolated to babies in hospitals. Sick and premature infants are more at risk for these infections. Please see ‘Handling of breastmilk’ for more information on proper handling techniques.

Theoretical risks
While there is risk of disease transmission, there are other, theoretical, risks of informed milk sharing:

  • Unwanted contact from adults who seek milk for non-medical needs,5
  • Harassment by donor/recipient,
  • Possible sabotage by recipient or donor,
  • Transmission of pathogens that could cause a baby to become sick or die,
  • Legal action, founded or unfounded, in case of bad outcome.6

Risk of pasteurized versus raw breastmilk
Sick and premature babies are at risk for neonatal hospital acquired infections. The lack of anti-effective properties in pasteurized milk can put a baby at risk, especially when a baby is sick or premature. Please see ‘What about premature babies?’ for more information about the effect of heat-treating on breastmilk.

In this previous but valuable study on the effect of routine screening of raw breastmilk and donor milk for premature babies, the authors discuss that while the data clearly document that premature infants fed raw expressed human milk are frequently exposed to large numbers of bacteria, no adverse events directly related to consuming this milk were documented.

The lack of anti-effective properties in pasteurized milk can put a baby at risk, especially when a baby is sick or premature. Please see ‘What about premature babies?’ for more information about the effect of heat-treating on breastmilk. Please see ‘Why breastmilk?’ for more information on the benefits of breastmilk.

Next: Breastmilk in a state of emergency


  1. Also see ‘Risks and ethics of breastmilk substitutes.‘ []
  2. Screening tests are designed to have a relatively high incidence of false positives in order to prevent any false negatives. While false positives happen to many people, they can occur more often during pregnancy. From the perspective of a milk bank which will be testing the donors on a regular basis, it makes sense to exclude anyone with a history of false positives since the cost of pursuing confirmations at every testing opportunity is not only prohibitive for a non-profit org, it also can lead to logistical issues with the milk received from the donor. This study does not follow up on the actual serological status of the subjects but, even per the most optimistic values, it is quite likely that many did not in fact have any current infections. []
  3. Donated breastmilk is, in most situations, milk expressed and/or stored for her own child. After blood screening of donors and education on safe expressing/handling/storing techniques, the risks to milk sharing are minimized. To suggest that this milk is not safe for sharing is to suggest that it is not safe for parents to feed their own babies with their expressed milk. We question this line of logic. []
  4. The same potential infections can occur when breastmilk substitutes are used in the same setting. Please also see ‘Risks and ethics of breastmilk substitutes’. []
  5. Please see ‘Who needs donated breastmilk’ for more information. []
  6. Donors may request recipients to provide blood and health screening(s). []

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