Tips for Expressing & Storing Breast Milk

Tips for expressing milk

  • Breastfeeding let-down requires certain hormones which are stimulated with the bonding and skin to skin contact of your baby. While expressing, it is important to try to relax, take some deep breathes and ideally be in a quiet, warm, relaxing area, away from distractions.
  • Emulate the skin to skin contact with your baby by gently massaging and stroking your breasts to help trigger the let-down.
  • Some mothers find pumping in front of their baby, looking at a picture of their baby or thinking about your baby and how much your breastmilk is helping them will encourage their let-down reflex.

Storage of breast milk

Breast milk does lose nutritional value the longer it is stored, so it is best to pump close to when the milk is required if possible. The most important part of expressing and storing breast milk is that both pump and storage containers are sterile and milk is stored correctly.

The New Zealand Ministry of Health provides the following guidelines

Storing breast milk

Ideally, milk fed directly from the breast is best. However, direct breastfeeding is not always possible, so expressed breast milk that has been correctly stored is the next best option for infants.

  • You should wash your hands before you express breast milk.
  • Store breast milk in a plastic or glass container with an airtight sealed lid (eg, a food storage container or bottle).
  • Milk should be stored in small portions to prevent waste – around 100–300 mL.
  • Date containers at the time of collection, and make sure caregivers use the oldest milk first.
  • Fresh or refrigerated milk retains beneficial properties and is preferable to breast milk that has been frozen.
  • If refrigerating or freezing breast milk, store it in a new container rather than adding it to previously refrigerated or frozen milk.
    – Adding expressed breast milk to frozen milk can cause the milk to thaw and then refreeze, which increases the risk of bacterial growth in the milk.
  • Wash containers and feeding equipment in hot soapy water, and then rinse.
  • If the infant is three months old or younger, the containers and equipment also need to be sterilised.
    – You can get sterilising equipment and tablets to make sterilising solution from your supermarket or pharmacy. Follow the manufacturer’s instructions carefully.
  • Alternatively, the containers and feeding equipment can be boiled.
  • When refrigerating, expressed breast milk should be stored in the bottom half of the fridge, at the back. Fridges should operate at 2–4 °C.
  • If you only need to store breast milk a short time, and don’t have access to a fridge or freezer, you can use an insulated cooler bag with ice packs.
    – Don’t use this method to store milk for more than 24 hours.
    – The ice packs should be in contact with the milk containers at all times.
    – Try not to open and close the cooler bag too often.

Note that these guidelines are for expressed breast milk that is fed to healthy, full-term infants who live at home.

Guidelines for storing expressed breast milk


Storage conditions Storage time Comments
Room temperature (< 26ºC) 4 hours Cover containers and keep them as cool as possible (eg, surround the closed container with a cool towel to help to keep the milk cooler)
Refrigerated 48 hours Store milk in the back of the main body of the fridge
Frozen 2 hours Store milk toward the back of the freezer, where the temperature is most constant
Freezer box in refrigerator Weeks
Separate door fridge/freezer 3–6 months
Separate deep-freeze 6–12 months

Using expressed breast milk

  • Frozen expressed breast milk can be thawed in the refrigerator or by placing the container in warm water until the milk has thawed.
  • Expressed breast milk should not be thawed or heated using a microwave because:
    – Microwaving destroys some of the milk’s immunological components
    – There is a risk of uneven heating and scalding.
  • Expressed breast milk can be warmed by placing the cup or bottle containing the milk in hot water.
  • Before feeding the infant, caregivers should swirl the container of milk to mix the fat portion back in and distribute the heat evenly.
  • They should test the temperature of the milk by shaking a few drops on the inside of their wrist. It should feel comfortably warm to the touch before being given to the infant.

Once the milk and the baby have begun feeding, any milk left should be discarded at the end of the feed.