Donor Milk and Milk Banks

What a milk bank is for

A human milk bank collects donated breast milk, screens the donors, pasteurises the milk, tests it, and supplies it to hospitals — overwhelmingly to neonatal units. UKAMB, the UK Association for Milk Banking, describes human milk as especially critical for premature babies, low birth weight and sick infants, or where there is insufficient milk from the baby's own mother.

The clinical reason is specific. UKAMB explains that donor breast milk is the preferred alternative to formula because it "still contains many of the protective factors (such as immunoglobulins) which help protect premature babies from infection", factors not present in formula made from cow's milk.

The condition that drives most donor milk use is necrotising enterocolitis, a serious gut condition mainly affecting premature babies. UKAMB states that babies who receive breast milk, whether their mother's own or donor milk, are at significantly lower risk than those who receive formula, and notes that a preterm baby's very immature intestine can digest and absorb breast milk more easily than formula.

The safety system behind it

In the UK there is a national standard. UKAMB states that "NHS and nonprofit milk banks adhere to the National Institute of Clinical Excellence Guideline (NICE) for the safe running of milk banks", meaning donor milk from those banks is "rigorously screened and from a single donor ensuring full traceability."

That guideline is NICE CG93, on donor milk bank service operation. It sets out donor recruitment and screening, serological testing, pasteurisation, quality assurance built on Hazard Analysis and Critical Control Point principles, equipment calibration and maintenance, staff training, batch recall and auditing. NICE makes the point that these recommendations depend on each other — the safety of donor milk rests on all of them being implemented, not a selection.

NICE also states that all donor milk administered in the NHS should come from milk banks that can demonstrate adherence to that guidance.

Who can donate

Donors are breastfeeding parents with milk surplus to their own baby's needs. UKAMB's summary of the screening is short: "Your blood will be tested for HIV, syphilis, hepatitis, and HTLV."

NICE sets out the exclusions in more detail. A potential donor is not eligible if she currently smokes or uses nicotine replacement therapy; regularly exceeds recommended alcohol levels for breastfeeding mothers; is using or has recently used recreational drugs; has previously tested positive for HIV 1 or 2, hepatitis B or C, HTLV type I or II, or syphilis; or is at increased risk of Creutzfeldt-Jakob disease.

Beyond the blood tests, NICE describes an interview covering general health, the age and health of her own baby, exposure to passive smoke, any medication or medical therapy, significant environmental or chemical exposure, recent exposure to infection, and recent medical interventions such as diagnostic radioactive isotopes.

Donors are not paid. UKAMB is clear that, in line with non-profit milk banking and blood and tissue donation worldwide, no payment is offered for milk, though reasonable expenses such as parking or travel for blood tests may be reimbursed.

How donating actually works

Contact your nearest milk bank first, because capacity, catchment and criteria vary and not every bank can accept every offer at every time. The bank arranges blood tests and sends out sterile bottles and labels. You express as you normally would, freeze the milk, label it, and the bank arranges collection or drop-off.

Milk arriving at the bank is thawed, pooled or kept single-donor depending on the bank's protocol, pasteurised, sampled for microbiological testing, refrozen and released only once the test results are clear. Every bottle is traceable back to the donor.

Who receives it

Priority goes to babies in neonatal care. Beyond that, UKAMB describes two other uses that vary by bank and by supply. Some banks may offer a small amount as "a bridge to breastfeeding" to support a parent while their own supply is being established, with clinical support. And where breastfeeding is impossible for health or medication reasons, some banks may be able to offer donor milk as an alternative to formula for a short period.

Both of those depend on availability, and both are arranged through a health professional rather than directly. If you want to ask, the route is your midwife, neonatal team or health visitor.

Informal milk sharing

Milk shared privately, through social media groups or between friends, is a different proposition from banked milk. It has not been screened, pasteurised, tested or traced. The risks are transmission of infections including HIV, hepatitis and HTLV; medications, alcohol or drugs passing through the milk; and bacterial contamination from collection, storage or transport.

People do it, often for understandable reasons, and it is not our place to lecture. But the distinction is factual: the safety system described above is the entire difference between the two, and none of it applies to milk arranged privately. If you are considering it, discuss it with a health professional first, and never buy milk from an online seller.

When to ask

Speak to your neonatal team, midwife or health visitor if:

• Your baby is in neonatal care and donor milk has not been mentioned.
• You are struggling to establish supply and want to ask about a bridging supply.
• You cannot breastfeed for medical reasons and want to know what is available locally.
• You have a freezer full of milk and want to donate it — ask them to point you to your regional bank.

UKAMB maintains a directory of milk banks across the UK and Ireland, and the Human Milk Foundation, which runs the Hearts Milk Bank, publishes detailed information for prospective donors.

Where to get real help

In the UK the National Breastfeeding Helpline is 0300 100 0212, run by the Breastfeeding Network and the Association of Breastfeeding Mothers, and open every day of the year. For milk banking specifically, contact UKAMB or your regional milk bank directly. In Ireland the HSE offers an "Ask our breastfeeding expert" live chat and email service.