Donating breast milk typically involves contacting a nonprofit milk bank, completing a health screening, passing a blood test, and shipping or dropping off your frozen milk. The process takes a few weeks from first contact to your first donation, and most banks ask for a minimum of about 200 ounces to start. Here’s what each step looks like in practice.
Why Donated Milk Matters
Nonprofit milk banks in North America dispensed a record 13 million ounces of pasteurized donor milk in 2025, a 12% jump from the year before, and demand continues to outpace supply. Most of that milk goes to neonatal intensive care units, where it feeds premature and critically ill newborns whose mothers cannot yet produce enough of their own. A Cochrane review of 11 trials involving over 2,200 infants found that donor milk cuts the risk of necrotizing enterocolitis, a life-threatening intestinal disease in preemies, roughly in half compared to formula.
Who Can Donate
Milk banks affiliated with the Human Milk Banking Association of North America (HMBANA) follow a standardized screening process. You need to be currently breastfeeding and in good general health. Most donors are parents who produce more milk than their own baby needs, though some people who have experienced a loss also choose to donate.
Certain factors will temporarily or permanently disqualify you:
- Tobacco or nicotine use, including vaping
- Cannabis or CBD products
- Recreational drug use
- Alcohol consumption (requires a deferral period)
- Certain medications, vaccines, or herbal supplements not on the bank’s approved list
- Recent blood transfusion or organ/tissue transplant
- Positive blood test for HIV, HTLV, hepatitis B, hepatitis C, or syphilis
- Risk factors for blood-borne illness, including Creutzfeldt-Jakob disease
You also cannot donate milk that has been heat-treated at home. Banks handle pasteurization themselves under controlled conditions.
The Screening Process Step by Step
Start by contacting a milk bank near you. HMBANA’s website lists nonprofit banks across the U.S. and Canada. The screening has three parts: a written health questionnaire, a verbal interview, and a blood draw.
The questionnaire and phone interview cover your medical history, current medications, lifestyle habits, and diet. Banks also contact your healthcare provider and your baby’s pediatrician to verify that donating won’t compromise your own infant’s nutrition. The blood test screens for HIV-1, HIV-2, HTLV (a virus linked to certain cancers), hepatitis B, hepatitis C, and syphilis. All results must come back negative. The blood draw is typically done at a lab near you at no cost. From first contact to clearance, expect the process to take roughly two to four weeks.
Once you’re approved, the milk bank stays in touch throughout your donation period. You’re expected to report any changes in your health, new medications, or new supplements so the bank can determine whether your milk is still eligible.
How Much Milk You Need
Minimum donation requirements vary by bank, but a common threshold is 200 ounces for your first donation. That sounds like a lot, but if you’re regularly pumping extra milk, it can accumulate over several weeks or months in your freezer. After your initial donation, many banks accept smaller quantities with no minimum.
If you already have a stash of frozen milk and you’re wondering whether it’s still usable, the CDC recommends that frozen breast milk is best used within six months, though it’s acceptable up to 12 months in a standard home freezer.
Storing and Packing Your Milk
Label every container with the date and time you pumped. Use storage bags or bottles approved by your milk bank, and freeze the milk as soon as possible after expressing. Keep it in the back of the freezer, not the door, where temperatures fluctuate more.
When it’s time to send your milk, pack it frozen. You’ll need a sturdy cooler, dry ice (about two pounds per cooler), zip-lock bags, newspaper for insulation, and tape for sealing. Place the dry ice wrapped in paper at the bottom, layer newspaper over it, then nestle the sealed bags of frozen milk on top with crumpled newspaper padding the gaps. Label both the inside and outside of the cooler with your name and the milk bank’s address. Number each container so the bank can confirm everything arrived.
Many milk banks also offer local drop-off sites at hospitals or lactation centers, which eliminates the need for shipping altogether. Some banks even arrange courier pickup at your home. Ask your bank which options are available in your area.
If You’re Shipping by Air
Airlines classify breast milk as a bodily fluid, and dry ice counts as a hazardous substance, so you’ll need to declare both when checking in. Have your shipping labels and tape ready at the counter in case security needs to inspect and reseal the cooler. Contact your airline ahead of time for their specific rules on dry ice weight limits and packaging.
What Happens to Your Milk After Donation
At the milk bank, donations from multiple screened donors are pooled and then pasteurized using the Holder method: heating to 62.5°C (about 144.5°F) for 30 minutes. This kills bacteria and viruses while preserving most of the milk’s immune and nutritional properties. After pasteurization, samples are cultured to confirm no bacterial contamination survived. Milk that passes testing is frozen and distributed, primarily to hospital NICUs, where it’s prescribed by a physician for the most vulnerable infants.
Peer-to-Peer Milk Sharing
Some parents share milk directly with other families rather than going through a bank. This is sometimes called informal or community milk sharing, and it skips the pasteurization and blood testing that banks provide. If you go this route, whether as a donor or recipient, there are ways to reduce risk.
Meet the donor or recipient in person rather than arranging exchanges solely online. Never purchase milk from strangers on the internet. Ask the donor about their health history, medications, and lifestyle, the same questions a milk bank would ask. Request recent blood test results and have a healthcare provider review them. Limit the number of donors to reduce exposure to unknown risks. Work together to ensure the milk is pumped, stored, and transported under clean, cold conditions.
Flash heating milk at home is sometimes suggested as a DIY safety step, but it has not been well studied or proven effective in informal sharing situations. The safest option remains donating through a regulated milk bank, where every batch is screened, pasteurized, and tested before reaching a baby.