Breastmilk: Pumping, Collecting, Storing
The following are general guidelines for collecting and storing breastmilk when using
a hospital-grade electric breast pump. If the neonatal intensive care unit (NICU)
gives you more specific instructions, follow their recommendations.
Before you begin to pump, read the instruction manual for the breast pump and collection
kit you are using.
Keep it sterile
Breastmilk is not sterile, but you do not want to introduce "outside" bacteria when
getting ready to pump, during pumping, or when storing milk or transporting it to
Always wash and rinse your hands thoroughly before handling any clean pump parts,
your breasts, or the milk collection bottles or containers.
Certain pump collection kit parts must be cleaned and sterilized according to the
instruction manual. Most recommend thorough cleaning of these parts after each use
and sterilizing parts at least once in 24 hours.
The collection bottles or containers that attach to the pump and are used to collect
and store your milk should be sterile (boiled or steamed). The NICU may be able to
supply the milk collection containers.
Try different settings
You may have to try different methods and settings on the breast pump before you find
ones that work best for you. The following are some general tips:
You can moisten the rim of the breast flange before pumping if you want to create
a better seal on the breast.
Some mothers prefer to center the breast flanges on the nipple and areola first and
then turn the pump on. Others turn the pump on first and then place the flanges over
Start the pump at the low or minimal suction setting. Gradually move the setting to
increase the level of suction. The level usually is set as high as comfort allows.
Decrease the suction if it causes discomfort.
Suction can't be maintained if the seal of the flange on the breast is broken, so
check the seal of the flange periodically. Also watch for the rhythmic pull and release
of the nipple and areola within the flange.
Expect to pump for a few minutes before you see a steady flow of milk.
Don't fill collection bottles more than two-thirds full so that milk does not flow
back. This also allows the milk to expand if it is to be frozen. If you easily fill
bottles, have more collection bottles ready. Stop and change bottles as needed. If
your baby takes more than the amount in one bottle at a feeding, you might attach
collection bottles that can hold a larger amount to the breast flange.
When you are ready to stop pumping, use a clean finger to press in on your breast
just above the pump breast flange. This should break the seal between the flange and
the breast tissue. If milk has pooled in a flange, tilt it so that milk can drain
into the collection bottle as you remove the flange. Then turn off the breast pump.
Some mothers turn the breast pump off first, and then break the seal between the flange
and the breast.
Storing your breastmilk
If you pumped both breasts at once and the total amount of milk will fill one bottle
no more than two-thirds full, you may combine the contents in one bottle by carefully
pouring the milk from one sterile container into the other. Don't combine milk from
different pumping sessions when pumping for a high-risk baby.
Label the collection container(s) right away
Labels should include the baby's name, the date, the time of day pumped, and any medicines
or substances, such as cigarette byproducts that you have taken or been exposed to
since the last pumping session.
If using unrefrigerated, fresh breastmilk, it should be fed to a baby within an hour
of being pumped. Don't leave milk out longer than 30 to 60 minutes when it is to be
given to a high-risk baby. This risks contamination—something a high-risk baby does
It is not always possible to give a baby fresh breastmilk. Or you may get more than
needed for a feeding and want to save the milk for later use. In these cases, refrigerate
your milk in the labeled collection bottles right away. The refrigerator should be
at a temperature of 32°F to 39°F (0°C to 3.9°C).
Freeze labeled collection bottles if the milk will not be used within 24 to 48 hours.
The NICU staff will let you know whether they are using 24 hours or 48 hours as a
Don't freeze breastmilk that has been refrigerated for more than 24 to 48 hours. Although
milk has been shown to be safe when refrigerated for several days, experts usually
recommend freezing milk sooner when it is to be given to a high-risk baby.
Freeze breastmilk in small amounts so that only what your baby needs is thawed each
time. After breastmilk has been thawed, it must be used within 24 hours (if thawed
in the refrigerator), or 4 hours if it was warmed, or it must be discarded. Your baby's
nurse can help you to know how much your baby needs daily.
Frozen breastmilk may be kept:
Up to 2 weeks if the freezer compartment is within the refrigerator. You must open
the refrigerator door to reach the freezer with this model.
3 to 6 months in a freezer that is part of a refrigerator unit but has a separate
6 to 12 months in a separate, 0°F (-18°C) "deep" freezer
Transporting refrigerated or frozen breastmilk
Place it in an insulated bag or cooler with a cool pack. The farther you live from
the NICU, the more likely it is that you will have to pad the inside of the cooler
with extra cold packs to keep frozen milk from thawing.
Fresh breastmilk contains the most active anti-infective properties. Refrigerated
breastmilk has fewer anti-infective properties than fresh milk, and frozen breastmilk
has the least.
The following are general guidelines for thawing frozen milk:
The oldest milk should be used first, unless recently expressed milk is recommended.
Thaw breastmilk by placing the collection container in the refrigerator. If you need
the milk more quickly, you can hold it under warm, running water or place it in a
cup, pot, bowl, or basin of warm water.
Don't thaw breastmilk at room temperature, in very hot water, or in the microwave.
Microwaving can create hot spots. Both microwaving and heating in very hot water may
decrease the amount of certain anti-infective properties in the milk.
Your milk separates during storage, and the cream rises to the top. Gently swirl,
or rotate, the collection bottle of milk to mix it together. Don't shake it vigorously.
Don't refreeze milk once it has been thawed. Thawed milk must be used within 24 hours
for a baby in the NICU. (It is safe to give milk that has been thawed for 24 to 48
hours after the baby is home.)
Taking care of your breast pump and collection kit
It is important to maintain the breast pump and collection kit in good working order:
Read the instruction manual and follow the recommendations for cleaning pump equipment,
unless given special guidelines by the NICU.
The pieces of the collection kit come apart for individual cleaning.
The pump itself and the tubing portion of the kit do not have to be cleaned, and they
should remain dry or they will not work appropriately. (These pieces of equipment
never come in contact with milk that is to be stored for the baby.)
After each use, rinse all parts that come in contact with the breast or milk in cool
water first. (A cool rinse removes residual milk without coagulating hard-to-clean
protein.) Then thoroughly clean these same parts in hot, soapy water. Rinse in hot
water, and air dry between each use.
Most manufacturers recommend boiling or sterilizing all parts that come in contact
with the breast or milk once a day. Sterilizing can be done in the microwave in reusable
sterilization bags made by the pump company. (Check the instruction manual.)
Don't use a dishwasher to clean or sterilize the parts that come in contact with the
breast or milk unless you have received permission from the NICU and the instruction
manual suggests this method as a choice.