Introduction to Breast Pumping

breast pumping


As you start to prepare breast milk for your baby’s diet, you must decide how to store the extracted milk until it is needed. As a new mother pump you should consider some aspects of milk storage before you start with your planned pumping routine.
Once you start pumping out milk, you need to know how long your breast milk will stay fresh, whether stored in the refrigerator, freezer or at room temperature. You also need to know how to safely heat or thaw milkThe following articles discuss everything you need to consider to properly store and feed your expressed breastmilk.

Breastmilk Storage Guidelines

The following guidelines can help to ensure that your expressed breastmilk remains fresh for your child’s feedings.

  • Room Temperature (66-72 ˚F, 19-22 ˚C) fresh for up to 10 hours
  • Refrigerator (32-39 ˚F, 0-4 ˚C) store fresh milk for up to 8 days
  • Freezer Compartment in Refrigerator store for 2 weeks
  • Freezer with Separate Door from Refrigerator remains fresh for 3 to 4 months
  • Deep Freezer (0 ˚F, -19 ˚C) store milk safely for up to 6 months


Refrigeration is the recommended method for storing breastmilk because it preserves the natural immunity factors of the milk better than freezing.

Freezing Refrigerated Milk

It is recommended that fresh milk be chilled prior to freezing; however, milk that has been refrigerated for a day or two should not be frozen. Milk that has been refrigerated that long should not be frozen because although refrigeration has slowed down the enzyme activity it has not stopped completely and it has a greater potential for bacteria growth.

To be on the safe side any milk that needs to be frozen should be placed in the freezer within 6 hours of refrigerating to ensure that it is frozen at its freshest state.

Adding Fresh Milk to Frozen Milk

Many mothers often wonder whether it is safe to add fresh milk to frozen milk. Fresh milk can be layered onto frozen milk as long as the fresh milk is chilled and is less than the amount of milk that is already frozen. This will prevent the milk from thawing and refreezing.

Separation of Breastmilk

Breastmilk separates into a fatty layer and a milky layer after it has been refrigerated, this is normal and is not a sign of spoilage. Gently swirling the milk before feeding will help mix the layers together.

Proper Labeling

Be sure to always label your expressed milk with the date before storing. This will help you to ensure that you always use the oldest available fresh milk first. You should also include your baby’s name on the label if the milk will be stored with milk for more than one baby.

Helpful Storage Tips

  • When storing your milk, always be sure to place it in the back of the refrigerator or freezer to ensure that it stays cool even when the refrigerator or freezer door is opened and closed throughout the day.
  • Always wash your hands thoroughly before handling any expressed milk.
  • Store breastmilk in the amount that your baby eats during each feeding or in small 1 to 2oz. amounts to limit the amount of milk that is wasted.

Choosing A Breastmilk Storage System

There are endless options available for storing breastmilk. Everything from glass and plastic bottles to freezer bags and trays has been designed specifically for storing expressed milk. With so many storage systems to choose from, selecting one storage method can be a challenge.

Which storage system you will use will be determined by:

  • How much breastmilk you plan to store (at any given time)?
  • How much storage space you have available?
  • How often you plan to use your expressed breastmilk for feedings?
  • How long you anticipate storing your expressed milk?


Healthcare professionals and La Leche League recommend storing expressed breastmilk in one of the following three container types: glass, clear, hard plastic (polycarbonate) or cloudy, hard plastic (polypropylene).

Freezer Storage Bags and Disposable Bottle Liners

Plastic storage bags are a great space saving storage option if you have limited freezer space for your expressed milk. However, you should be sure to only use freezer storage bags and not plastic bottle liners when storing breastmilk.

Breastmilk freezer storage bags are designed for storing and freezing breastmilk. These bags easily fit onto your breast pump and allow you to express milk directly into the bag. Freezer storage bags are thick, pre-sterilized and seal easily. They also have an area designated for labeling the milk with date.

Disposable bottle liners are designed for infant feeding not breastmilk storage. Bottle liners are not recommended for storage because the thin plastic cannot protect the milk from freezer burn, the bags do not seal easily, there is no area for labeling and the seams of the bag may burst during freezing and leak during thawing.

Convenient Storage

When selecting a milk storage system, convenience often takes precedence over the decision. For this reason mothers often opt for plastic storage bags because they take up less space and are single use items that do not require cleaning. However, while the bags are convenient for storing they are less convenient for feeding because pouring milk out of bags can be awkward.

Breastmilk storage trays are another convenient storage method. These trays are made of flexible plastic that allows you to store milk in convenient one ounce cubes. The small cubes thaw very quickly and make it easy to prepare small bottles to avoid waste.

Other mothers find it far more convenient to pump, store and feed from the same container. By using bottles for storage the repeated transfer of the milk from one container to another is eliminated. Hard, clear plastic bottles are great for storing and feeding refrigerated and frozen milk.

Regardless of which storage system you choose, you should always be sure to clean your storage containers properly prior to use. For tips on keeping your pump and storage containers clean refer to this website:

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