[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Nursing](https://durgical.com/en/nursing/) › [Maternal and child nursing](https://durgical.com/en/nursing/areas/maternal-child/) › Expressing and storing breast milk, human milk banks, and safe formula preparation when it is needed # Expressing and storing breast milk, human milk banks, and safe formula preparation when it is needed - Procedure The nurse teaches hand expression, safe storage and thawing of breast milk, explains milk banks, and teaches safe formula preparation when it is truly needed. Updated Nov 13, 2026 ## Key points - Freshly expressed milk: up to 4 hours at room temperature (25 °C or cooler), up to 4 days in the fridge, best within 6 months in the freezer (up to 12). - Thawed milk: use within 24 hours once fully thawed in the fridge, within 2 hours once warmed; never refreeze. - Never thaw or warm milk in a microwave: it creates hot spots that burn the mouth. - Hand expression: fingers in a C shape a few centimetres back from the nipple, squeeze and release in a rhythm, move around the breast. - Prepared formula is used within 2 hours and leftovers are thrown away. On this page - The basics Key points - What it is - Indications - Equipment - Step by step (and why) - Next step: when to call for help - Elsewhere in DurgiPedia - Clinical Complications - Safety Contraindications and precautions - Study Test yourself - Connections Connections ## What it is When a baby cannot breastfeed directly, for example because it is preterm, ill or apart from its mother, expressed milk keeps it fed with breast milk and keeps the mother's supply going. The nurse teaches the mother to express by hand or with a pump, to collect and label the milk, and to store, thaw and warm it safely. In Colombia, human milk banks collect donated milk, check and pasteurise it and give it to hospitalised newborns who need it. When formula is medically needed, the family learns to prepare it hygienically, because powdered formula is not sterile. ## Indications - Baby in a neonatal unit, preterm or too ill to feed at the breast. - Baby that cannot latch or suck well, or a mother apart from her baby. - Breasts uncomfortably full, or to build up the milk supply. - Donation to a human milk bank by a healthy breastfeeding woman with surplus milk. ## Contraindications and precautions - Wash hands with soap and water before expressing or handling milk. - Do not squeeze the nipple or slide the fingers over the skin: it makes the nipple sore. - With an electric pump, build suction up slowly; a pump must never hurt or bruise. - Never refreeze thawed milk and never use a microwave. - Formula only when there is a medical reason; for higher-risk babies the family follows the extra hygiene steps. ## Equipment - Clean food-grade glass or plastic containers with tight lids, or breast milk storage bags. - Labels for the date of expression (and the baby's name in a unit or nursery). - A manual or electric pump if used, cleaned and sterilised before each use. - A fridge, a freezer, and a cool box with ice packs for transport. - For formula: safe boiled water and clean, disassembled bottles and teats. ## Step by step (and why) - Wash hands with soap and water and have a clean container ready — milk is easily contaminated. - Massage the breast gently from the armpit towards the nipple — it helps the milk to flow. - Place thumb and finger in a C a few centimetres back from the nipple, squeeze and release in a rhythm — this empties the ducts without hurting. - When the flow slows, move the fingers around the breast, then change breasts — empties all areas. - Close the container, label it with the date and store it away from the fridge door — the door warms each time it opens. - Thaw the oldest milk first, in the fridge or in warm water; swirl it and test a drop on the wrist — mixes the fat and avoids burns. - Give the expressed milk as the team indicates and record the feed — keeps track of what the baby receives. - In the unit, follow the milk protocol: the mother's own fresh milk for her baby, donor milk from the milk bank when prescribed. - If formula is needed, clean hands and surfaces, use boiled water and cool the bottle to body temperature before feeding — powdered formula is not sterile. ## Complications - Contamination of milk or formula and infection in the baby. - Mouth burns from milk heated in a microwave. - Sore or damaged nipples from squeezing, sliding fingers or strong suction. - A falling milk supply if the mother expresses rarely. ## Next step: when to call for help - Red, painful breast or fever in the mother: tell the doctor and keep emptying the breast. - Baby not gaining weight, few wet nappies or poor feeding: tell the team. - Doubt about how long milk or formula has been stored: discard it and tell the family why. - A mother who wants to donate: refer her to the human milk bank, which checks her health before she donates. ## Test yourself Think of the answer, then tap the question to see it. ## How long can freshly expressed breast milk be kept in the fridge, according to CDC? Up to 4 days. ## Why should breast milk never be thawed or warmed in a microwave? It creates hot spots that can burn the baby's mouth and can destroy nutrients. ## Where are the fingers placed for hand expression? In a C shape a few centimetres back from the nipple, just outside the areola, without squeezing the nipple itself. ## What does a human milk bank do with donated milk before giving it to newborns? Checks its quality, pasteurises it and tests it again before releasing it to hospitalised newborns. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/nursing/expressing-and-storing-breast-milk-human-milk-banks-and-safe-formula-preparation/) ## Elsewhere in DurgiPedia - [Lactation](https://durgical.com/en/physiology/lactation/) ## Connections ## Related 3 - [Breastfeeding support: latch, positions and common problems](https://durgical.com/en/nursing/breastfeeding-support-latch-positions-and-common-problems/) - [Kangaroo mother care](https://durgical.com/en/nursing/kangaroo-mother-care/) - [Caring for the preterm and low-birth-weight newborn: developmental care, feeding, skin and pain](https://durgical.com/en/nursing/caring-for-the-preterm-and-low-birth-weight-newborn-developmental-care-feeding-s/) [← All of nursing](https://durgical.com/en/nursing/) Educational content for students; it does not replace your institution's protocols, supervised clinical training or a prescriber's order. Dose-calculation examples use made-up numbers: they are educational, not a clinical order. Sources: [Breast milk storage and preparation](https://www.cdc.gov/breastfeeding/breast-milk-preparation-and-storage/handling-breastmilk.html) (Centers for Disease Control and Prevention (CDC), 2026); [Expressing breast milk](https://www.nhs.uk/baby/breastfeeding-and-bottle-feeding/breastfeeding/expressing-breast-milk/) (NHS (National Health Service, England), 2026); [Preventing Cronobacter infection: safe preparation of powdered infant formula](https://www.cdc.gov/cronobacter/prevention/index.html) (Centers for Disease Control and Prevention (CDC), 2025); [Banco de leche humana: BLH en Colombia](https://www.minsalud.gov.co/sites/rid/Lists/BibliotecaDigital/RIDE/VS/PP/SNA/donacion-bancos-de-leche-humana-mayo-2015.pdf) (Ministerio de Salud y Protección Social de Colombia, 2015). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/nursing/expressing-and-storing-breast-milk-human-milk-banks-and-safe-formula-preparation/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/nursing/expressing-and-storing-breast-milk-human-milk-banks-and-safe-formula-preparation/