New mothers know the “breast is best” mantra by heart.

“Yet, there are times when it’s just not possible to latch baby to the breast and a mother may just need to turn to expressing and storing her breast milk just so she can keep her milk supply going and baby will have a constant supply,” shares Dr Varsha Atul Shah, Senior Consultant, Department of Neonatal and Developmental Medicine, Singapore General Hospital (SGH), a member of the SingHealth group.

Here is all you must know about breast milk expressing, or more commonly known as breast pumps or 'pumping'.

3 Ways to express breast milk

  1. Manual hand-expression

    Before expressing breast milk by hand, wash hands with soap and water. Place the forefinger and thumb at the edge of the areola (the dark area of the breast) and press back firmly against the breast. Then bring fingers together and compress the areola using the finger pads. It is encouraged to compress the breast in a rhythmic manner when expressing milk.

  2. Manual pumping

    Mothers are advised to use the piston-type pump, which allows for control over the suction. Ensure that the flange of a pump is placed over the areola to form a complete seal, just as baby’s mouth would when she is being breastfed. Pump continuously for five minutes, alternating each breast and massaging the breast in between pumps. Each session should not last more than 30 minutes in order not to tire out the mother.

  3. Battery or electric pump

    If choosing to use the battery-operated or electric pump, remember to begin with minimum power before increasing the intensity to which one is comfortable with. Fully automatic electric pumps and those that allow for double pumping work to reduce pumping time and promote milk production.

General tips on expressing breast milk

  • Frequency of expression
    This should be between 8 and 12 times in a 24-hour period during the initiation of milk supply – it includes one or two night-time expressions. The frequency is strongly recommended especially in the first two weeks of breast milk expression.

  • Length of expressing episodes
    Each episode should last approximately 20 to 30 minutes, or until the milk flow stops or slows down. Swap breasts frequently – two to three times during each expressing episode is recommended. Initial volume is small but it will increase dramatically within 72 hours.

How to feed stored milk

To feed baby with the expressed milk, simply thaw – either by transferring it earlier to the refrigerator or by warming the milk in warm water or a warmer for 10 minutes.

Some important points to note:

  1. Do not boil the milk or warm in a microwave oven.

  2. Do not refreeze the milk once it has been thawed as it may be contaminated.

  3. Discard any excess milk left in the bottle after a feed.

  4. Newly expressed milk should not be added to earlier stored milk and then re-stored.

In general, freezing of milk is not encouraged for premature babies who are still hospitalised. “Direct nursing is always encouraged once the baby is able to latch on and suck, and the mother is well,” says Dr Varsha.

Ideally, babies should receive their own mother’s milk directly from the breast through suckling.

Reasons for breast milk expression

There are several reasons why a mother would require expressing her breast milk. These include:

  1. Feeding an unwell or premature baby

  2. When mother and baby are separated due to medical and non-medical reasons

  3. To reduce breast engorgement

  4. If the mother’s milk ducts are plugged or blocked

  5. If the mother has flat/inverted nipples

  6. If the mother is suffering from painful inflammation in her breasts (mastitis)

  7. If the mother is planning to return to work or need to spend time away from baby

Techniques to encourage your let-down reflex when expressing

The let-down reflex occurs when baby starts sucking on the breast and she is properly latched on. However, if breast milk needs to be expressed instead, a mother can try these steps to ease the expressing breast milk:

When preparing to express milk

The mother should consciously try to relax, using whatever method suits her, and in a quiet, warm, relaxing area, and away from distractions. While expressing, she must take slow, deep breaths. She could also consider expressing in the place where she would usually sit to feed her baby. Some mothers have a warm drink first or listen to soft music. Warmth (expressing after a warm shower or placing a warm face washer on the breast for a few minutes before starting) may also help.

To start expressing milk

Gently massage breasts by stroking down towards the nipple, and gently rolling the nipple between fingers. While one can’t actually push the milk out of her breasts by massage, it can help trigger the let-down reflex from touching the breasts.

Thinking about baby and how much breast milk is helping her will also encourage the let-down reflex. For a baby who is born premature or sick in hospital, a mother might find it easier to express near her baby’s crib or just after she visits her. If the mother is away from her baby, having a photo of the baby to look at can help too.

During breast milk expression

The mother should have someone around to accompany and support her during milk expression. Many mothers find they manage much better when they have an encouraging partner or friend, who might sometimes just be there to give a massage on her neck or back, and encourage her positively.

Storage of expressed breast milk

  1. Storage containers
    These can include glass or sterilised bottles, disposable sterile breast milk containers and disposable storage bags. All containers, caps and funnels used in the expression and collection of breast milk should be properly sterilised. This can be done either by placing them in boiling water for five to 10 minutes, through steam sterilisation or by sterilisation tablets immersed in clean water.

  2. Volume of milk
    It is important to always store the expressed milk in feed-size amounts in sterilised bottles. This will prevent wastage and make it convenient during feeding times. Containers should always be labelled with the name, date and time of collection, especially when it is to be transported to the hospital. It should be refrigerated at once after expression. Always remember to use the milk expressed at the earlier date.

Home use: Storage guide for breast milk

Breast MilkRoom temperatureRefrigerator 4°CFreezer
Freshly expressed into a closed container6 to 8 hours (26°C or lower). If a refrigerator is available, store milk in itNo more than 72 hours. Store at the back, where it is coldest
  • 2 weeks in freezer compartment inside refrigerator (-15°C)
  • 3-6 months in freezer section of refrigerator with separate door (-18°C)
  • 6–12 months in deep freeze (-20°C**)
Previously frozen (thawed in refrigerator but not warmed)4 hours or less (i.e. the next feeding)Store in refrigerator for 24 hoursDo not refreeze
Thawed outside refrigerator in warm waterFor completion of feedingHold for 4 hours or until next feedingDo not refreeze
Infant has begun feedingOnly for completion of feeding, then discardDiscardDiscard

Breast milk transportation guide

To avoid infection, special care should be taken when storing breast milk for premature babies in hospitals. The moving of stored milk from place to place must maintain the cold chain.

When transporting expressed milk, put the bottles in a cooler box with ice packs. Transfer the bottles into the refrigerator once you have reached your destination.

Always give the freshly expressed breast milk to baby, where possible.

It is not necessary to freeze your breast milk unless you have so much excess that your baby is unable to consume it within 48 hours. Properly refrigerated milk can be kept for 24 to 48 hours.

“However, at SGH’s Department of Neonatal and Developmental Medicine, the policy is to discard the milk after 24 hours to lower the risk of infection in premature babies,” shares Dr Varsha.