Breastmilk Storage – Guidelines for premature infants

Milk storage guidelines are different for premature or hospitalized babies, as these babies are more at risk for infection — discuss these guidelines with your baby’s health care provider.

For milk storage information for healthy, full term babies, see Breastmilk Storage & Handling.

(Guidelines for Premature Infants)
Storage Time
Freshly expressed milk (Refrigerate ASAP if not using within 4 hours)
Room temperature 1-4 hours
Refrigerated Milk (Store at back; do not store in door.)
Refrigerator (fresh milk) 48 hours
Refrigerator (completely thawed milk, fortified milk) 24 hours
Frozen Milk (Store at back; do not store in door. Do not refreeze.)
Freezer compartment inside refrigerator door Not recommended
Freezer compartment with separate door 3 months
Deep freeze (not attached to refrigerator) 6 months
Transporting milk (Fresh, Refrigerated or Frozen)
Pack in insulated cooler with ice or “blue ice” 24 hours
Save ALL the milk you pump – your milk is important to your baby.
Storing your milk: Label storage container with your baby’s name and date/time of expression. Rigid plastic or glass storage containers are best.

The fresher the better! When possible, take your pump kit to the hospital to pump fresh milk for baby’s next feeding. When pumping at home, refrigerate milk if you plan to get your milk to the hospital within 24 hours; otherwise freeze the milk. Milk that is in the refrigerator may be frozen within 48 hours.

Store milk in 1-4 ounce portions to avoid waste and for easier thawing/warming. Milk expressed from each breast at the same time may be combined into one container. Fill container no more than 2/3 full to allow for expansion when freezing. Cap with a solid lid (not a bottle nipple).

Thawing frozen milk: Thaw overnight in the refrigerator, or stand container in a bowl of warm water,without wetting lid, until thawed (up to 20 minutes).

Previously frozen milk may be stored in the refrigerator for up to 24 hours after it has finished thawing. Do not refreeze.

Warming your milk: Heat water in a cup or other small container, then place container of milk in the water to warm. Do not place milk in boiling water. NEVER microwave human milk or heat it directly on the stove.

Handling: The cream will rise to the top of the milk during storage. Gently swirl milk (do not shake) to mix before checking temperature and offering to baby.

If baby does not finish milk, the unused warmed milk should be discarded at the end of the feeding.



California Perinatal Quality Care Collaborative (CPQCC). Nutritional Support of the Very Low Birth Weight Infant Toolkit. Palo Alto, CA: CPQCC, 2008.

Riordan J and Wambach K. Breastfeeding and Human Lactation, 4th ed. Boston and London: Jones and Bartlett; 2010, p. 437-440.

Lawrence RA. Milk banking: the influence of storage procedures and subsequent processing on immunologic components of human milk. Adv Nutr Res. 2001;10:389-404.

Eteng MU, Ebong PE, Eyong EU, Ettarh RR. Storage beyond three hours at ambient temperature alters the biochemical and nutritional qualities of breast milk. Afr J Reprod Health. 2001 Aug;5(2):130-4.

Tully MR. Recommendations for handling of mother’s own milk. J Hum Lact. 2000 May;16(2):149-51.

Arnold LDW, ed. Recommendations for collection storage, and handling of a mother’s milk for her own infant in the hospital setting. West Hartford, CT: Human Milk Banking Association of North America; 1999.

Hamosh M, Ellis LA, Pollock DR, Henderson TR, Hamosh P. Breastfeeding and the working mother: effect of time and temperature of short-term storage on proteolysis, lipolysis, and bacterial growth in milk. Pediatrics. 1996 Apr;97(4):492-8.

Pardou A, Serruys E, Mascart-Lemone F, Dramaix M, Vis HL. Human milk banking: influence of storage processes and of bacterial contamination on some milk constituents. Biol Neonate. 1994;65(5):302-9.

Quan R, Yang C, Rubinstein S, Lewiston NJ, Sunshine P, Stevenson DK, Kerner JA Jr. Effects of microwave radiation on anti-infective factors in human milk. Pediatrics. 1992 Apr;89(4 Pt 1):667-9.

Sigman M, Burke KI, Swarner OW, Shavlik GW. Effects of microwaving human milk: changes in IgA content and bacterial count. J Am Diet Assoc. 1989 May;89(5):690-2.

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