How Long Does Breast Milk Last in the Fridge and Freezer?

Why you have seen four different answers

This is one of the few areas of infant feeding where the guidance genuinely conflicts, and the conflict is not a mistake. The Breastfeeding Network has documented the history: recommendations were collated from primary research in 2003, NICE reviewed them, and official UK storage advice changed from 24 hours in the fridge to up to five days at 4C or lower. Different bodies have made different assumptions since then about how clean expression is, how cold a domestic fridge really runs, and how much margin to build in. So the numbers below are all defensible and all different. Follow the body for the country you are in, and if you are in doubt, take the shorter figure.

Fresh expressed milk

• NHS (UK). Fridge: up to 8 days at 4C or lower; if you are not sure of your fridge temperature, or it is above 4C, use within 3 days. Ice compartment of a fridge: 2 weeks. Freezer at -18C or lower: up to 6 months. Cool bag with ice packs, for milk already chilled: up to 24 hours. The NHS gives no room-temperature figure at all.
• HSE (Ireland). Sealed outside the fridge: up to 4 hours below 20C. Fridge: 5 to 7 days, on a shelf and not in the door. Fridge freezer: 3 to 6 months. Deep freezer: up to 12 months. Cool bag with frozen ice packs: up to 24 hours.
• CDC (US). Room temperature at 25C (77F) or colder: up to 4 hours. Fridge: up to 4 days. Freezer: about 6 months is best, up to 12 months acceptable. Insulated cooler with frozen ice packs: up to 24 hours.
• Academy of Breastfeeding Medicine, Protocol #8 (2017). Room temperature: 4 hours optimal, 6 to 8 hours acceptable under very clean conditions. Fridge: 4 days optimal, 5 to 8 days under very clean conditions. Freezer: 6 months optimal, 12 months acceptable.
• healthdirect (Australia). Room temperature up to 26C: no more than 6 to 8 hours. Fridge up to 5C: no more than 72 hours. Freezer section of a fridge (-15C): 2 weeks. Freezer with a separate door (-18C): 3 months. Deep freeze (-20C): 6 to 12 months.

Milk that has been thawed

• NHS. Defrost slowly in the fridge where possible. Once defrosted, use it straight away. Do not re-freeze.
• HSE. Once fully thawed, 2 hours maximum at room temperature, or up to 24 hours in the fridge. Do not freeze twice.
• CDC. If thawed in the fridge, use within 24 hours, counting from when it is completely thawed rather than from when you took it out. Once brought to room temperature or warmed, use within 2 hours. Never refreeze.
• healthdirect. Thawed but not warmed: 4 hours at room temperature, 24 hours in the fridge. Thawed and warmed but not yet started: up to 4 hours in the fridge.
• ABM #8. Says there is little information on refreezing and that no recommendation can be made, which is a more honest position than a flat prohibition, but in practice every national body tells you not to.

Milk your baby has already drunk from

The NHS says that once your baby has drunk from a bottle of breast milk it should be used within 1 hour and anything left over thrown away. The CDC allows 2 hours. ABM Protocol #8 says the research is insufficient to give a firm figure but that discarding within 1 to 2 hours after the baby finishes seems reasonable. The difference is small and the practical answer is the same: store in small amounts so there is less to throw away.

Where in the fridge

Both the HSE and the CDC say the same thing and it matters more than most people realise: store milk at the back, on a shelf, not in the door, because the door swings between temperatures every time someone opens it. The HSE suggests the shelf above the vegetable compartment as the coldest part.

Containers and labelling

Sterilised hard containers or purpose-made breast milk storage bags are what the NHS and HSE both recommend. Leave about an inch of headroom because milk expands as it freezes. Freeze bags flat — they stack better and thaw faster. Label with the date, and with your baby's name if it is going to a nursery or hospital. Store in small amounts to avoid waste.

What is normal and not a sign of spoiling

Milk separates into layers in the fridge, with the creamier part on top. Swirl gently rather than shaking. Refrigerated and frozen milk often smell and look different from fresh, and most babies drink it happily. Colour varies with your diet and the time of day.

Two things every body agrees on

• Never microwave breast milk. It heats unevenly and creates hot spots that can scald your baby's mouth, and it damages the milk's protective components.
• Fresh beats frozen. Refrigeration preserves more of the milk's properties than freezing does, so use fresh or fridge milk first where you have the choice.

If milk has been left out too long

Judge it on time and temperature rather than on smell, because a soapy or metallic smell usually means lipase rather than spoilage. Milk left at warm room temperature well beyond the limits above should be discarded. If you are within the range but unsure — for example a cool bag that has been open repeatedly — use it for the next feed rather than storing it further.

Which milk to use first

Use fresh milk before refrigerated milk, and refrigerated before frozen. The Academy of Breastfeeding Medicine's protocol explains why: fresh milk contains current antibodies relevant to what you and your baby have recently been exposed to, and is highest in antioxidants, vitamins, protein, fat and probiotic bacteria compared with refrigerated or frozen milk. In the freezer, rotate oldest first. None of this means frozen milk is poor — it means the order is worth getting right when you have a choice.