Breast Milk: Pumping, Collecting, Storing
The following are general guidelines for collecting and storing breast milk 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:
Be sure to read the instruction manual for the breast pump and collection kit you
Breast milk 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.)
You may have to try different techniques 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/minimal suction setting and 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 cannot 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.
Do not fill collection bottles more than two-thirds full to avoid any back flow of
milk and to allow for expansion if milk is to be frozen. If you easily fill bottles,
have additional 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 breast milk:
Combining milk. If you pumped both breasts at once and the total amount of milk obtained 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. Do not combine
milk from different pumping sessions when pumping for a high-risk baby.
Label the collection container(s) immediately. Labels should include the baby's name, the date, the time of day obtained, and any
medicines or substances, such as cigarette by-products that you have taken, or been
exposed to since the last pumping session.
Fresh breast milk. Fresh breast milk contains the most active anti-infective properties. Refrigerated
breast milk has fewer anti-infective properties than fresh milk and frozen breast
milk has the least.
If using unrefrigerated, fresh breast milk, it should be fed to a baby within an hour
of being pumped. Do not 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 not need.
It is not always possible to give a baby fresh breast milk, or you may obtain more
than needed for a feeding and want to save the milk for later use. In these cases,
you should refrigerate your milk in the labeled collection bottles immediately. 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
Do not freeze breast milk 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 breast milk in small amounts so that only what your baby needs is thawed each
time. After breast milk has been thawed, it must be used within 24 hours (if thawed
in the refrigerator), or 4 hours (if warmed) or it must be discarded. Your baby's
nurse can help you to know how much your baby needs daily.
Frozen breast milk 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 breast milk. 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.
Thawing breast milk
The following are general guidelines for thawing frozen milk:
The oldest milk should be used first, unless recently expressed milk is recommended.
Thaw breast milk 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.
Do not thaw breast milk 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. Avoid vigorous shaking.
Do not 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.)
Do not 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 an option.