When you hear about babies in neonatal intensive care units (NICUs), especially those born too soon or too small, you might wonder how such tiny bodies get the nourishment they need to survive. For some, their own mother’s milk isn’t an option – and that’s where milk donors come in.

If you’ve ever considered donating your breastmilk, you might be curious about what the process actually involves. Where does your milk go? How is it stored safely? What happens before it reaches a baby in need?

Let’s take you through the journey – from your freezer to a NICU incubator.

Milk Donation Is Not a New Idea

While milk banks may seem like a modern innovation, the concept of sharing milk has been around for centuries. Wet nurses – women who breastfed another’s baby – were commonly used throughout history, especially in upper-class families or where mothers were unwell or had died. In fact, wet nursing was considered a formal occupation in many cultures.

Today’s milk banks are a continuation of that tradition, offering a safer, regulated, and more inclusive way for babies to receive human milk when their own parent’s milk is unavailable. It’s one of the most ancient forms of care, now backed by science and safety standards.

Who Can Donate Milk?

Before any milk is collected, milk banks follow strict criteria to make sure it’s safe for vulnerable babies. While the exact rules vary slightly depending on the milk bank, here are the general guidelines:

• You must be in good health and not taking medications that could pass through breastmilk (some exceptions apply – always ask).

• You’re a non-smoker, not using recreational drugs or regularly consuming alcohol.

• You’ve given birth in the last 6–9 months, though some banks may accept milk from longer ago.

• You usually need to be donating at least 100–150ml of milk.

• Blood tests are required for infections such as HIV, hepatitis B & C, HTLV, and syphilis.

• If you’re donating milk from home, freezer storage needs to meet safe temperature standards.

It’s okay if you don’t meet the criteria – your milk is still valuable for your baby. But if you do qualify, donating milk can be a life-changing act of kindness.

Keeping Milk Safe at Home

Milk collected at home must be handled with the same level of care you’d give to preparing milk for a premature baby. Here are a few safety guidelines to follow:

• Freezer Temperature: Your freezer must maintain a consistent temperature of -18°C or lower. Most milk banks will provide a thermometer and require regular logs to ensure compliance.

• Hygiene: All pumping equipment should be thoroughly washed and sterilised before and after each use. This includes pump parts, bottles, and storage containers.

• Label Clearly: Each bag or bottle of milk should be labelled with the date and time it was expressed, and your unique donor code if applicable.

• No Mixing: Don’t top up already frozen milk with fresh milk. Expressed milk should be frozen within 24 hours of collection.

Milk Collection – Sometimes by Bike!

Once you’ve built up a stash, your milk is collected and transported to the milk bank. Depending on where you live, this might be done via:

• Special courier services with cold chain systems.

• Volunteer drivers who are trained in safe milk transport.

• Or even milk bikes – yes, there are amazing volunteers who cycle across cities collecting milk in specially designed cool boxes!

Some milk banks provide insulated boxes and ice packs to ensure your precious donation stays frozen until it reaches the processing centre.

Pasteurisation and Testing

Once it arrives at the milk bank, your milk goes through a rigorous safety process before it’s sent out to hospitals.

1. Screening: The milk is checked for volume, temperature history, and any signs of contamination.

2. Pooling: Milk from several donors is often pooled to ensure consistency in nutrients.

3. Pasteurisation: The milk is heated gently to 62.5°C for 30 minutes, which kills harmful bacteria and viruses while preserving nutrients.

4. Testing: After pasteurisation, it’s tested again to ensure there’s no contamination.

5. Freezing: The milk is then frozen and stored, ready to be dispatched to NICUs across the country.

Giving Life to Tiny Babies

Donor milk can be life-saving for premature babies. Their immature digestive systems often struggle to handle formula, and their risk of serious gut infections (like necrotising enterocolitis) is much higher. Donor milk is the next best thing when mum’s own milk isn’t available.

Many parents – including myself – are forever grateful for donor mums who gave our babies a chance when we were recovering or struggling to produce enough ourselves.

Interested in Donating?

If you’re expressing milk and have more than your baby needs, donating could be one of the most powerful and generous things you’ll ever do. Not everyone is eligible, and that’s okay. But if you are, know that every drop could help a baby survive and thrive.

Ready to find out more?

You can contact your local milk bank through the UKAMB – United Kingdom Association for Milk Banking, which lists accredited banks across the UK.

Did you find this blog helpful?

Please like, comment, and subscribe so more families can feel supported and informed on their parenting journey.

And if you’re a NICU parent, a donor, or just someone with a big heart – thank you for being here.

References:

1. United Kingdom Association for Milk Banking (UKAMB) – www.ukamb.org

2. NHS Guidelines on Donor Milk – www.nhs.uk

3. Human Milk Foundation – www.humanmilkfoundation.org

4. NICE Guidance on Donor Breast Milk for Preterm Infants

5. Fildes, Valerie (1988). Wet Nursing: A History from Antiquity to the Present