Expressing breast milk: what pumping means, how often to do it and how long the milk keeps

Expressing is taking milk out of your breasts by hand or with a pump, so your baby can drink it later or so your breasts stay comfortable. Pumping is expressing with a breast pump. HealthHub says you can express by hand, or with a manual or electric pump. SGH's neonatal team says mums express when they are apart from their baby, when a baby is premature or unwell, or to keep breastfeeding after going back to work.

Why mums express

SGH's neonatal team lists the usual reasons: feeding a premature or unwell baby, being apart from your baby, easing engorgement or a blocked duct, flat or inverted nipples, mastitis, and going back to work. It still encourages feeding straight from the breast once your baby can latch and suck and you are well.

Many mums first express in hospital. If your baby cannot breastfeed for medical reasons, KKH encourages regular expressing so the first milk still reaches your baby. On its wards you can use an electric pump at no charge and pay only for the pre-sterilised disposable funnel and bottles.

How to express by hand

Hand expressing needs no equipment or power, and the NHS says it lets you target one part of the breast, which helps with a blocked duct. The NHS steps, in short:

1. Wash your hands and have a clean container ready.
2. Massage gently from the armpit towards the nipple to help your milk let down.
3. Make a C shape with your thumb and forefinger a few centimetres back from the nipple, just outside the darker areola.
4. Squeeze gently, release and repeat in a rhythm. Do not squeeze the nipple itself.
5. When the flow slows, move your fingers round the breast, then swap sides.

It should not hurt. If milk is slow to start, our page on the let-down reflex lists what helps.

Using a breast pump

HealthHub's advice is to wash your hands, use clean and sterilised parts, start at low pressure and switch breasts after about 20 minutes. The NHS warns that turning the suction up high straight away can hurt or damage your nipple, and that a pump should never bruise you or pull your nipple into the funnel. Funnels come in different sizes, so ask for help with fit.

SGH says fully automatic electric pumps and double pumping, both breasts at once, cut pumping time and help milk production.

How often to express

It depends on why you are expressing. If you are pumping instead of breastfeeding while your supply builds, SGH advises 8 to 12 sessions in 24 hours, including one or two at night, and says this matters most in the first two weeks. Each session lasts about 20 to 30 minutes, swapping breasts two or three times. Volumes start small and rise sharply within 72 hours, SGH says. For a premature baby, HealthHub suggests starting at 6 to 8 times a day, including at night.

For work, HealthHub suggests starting to express and store milk two weeks before your maternity leave ends, then expressing about every three hours, usually at lunch and before you leave. If you only want to ease full breasts, the NHS says to express just enough to feel comfortable so you do not overstimulate your supply.

How long expressed milk keeps

HealthHub gives these times for healthy babies: 4 hours at a room temperature of 25 degrees C, 24 hours in a cooler bag with an ice pack, 48 hours in the fridge at 4 degrees C, 3 to 6 months in the freezer of a two-door fridge and 6 to 12 months in a deep freezer at minus 20 degrees C. Thawed milk keeps 24 hours in the fridge. Once you warm it in a cup of warm water, HealthHub says to use it straight away or within an hour, and never to boil it or heat it in a microwave.

Our guide to pumping and storing breast milk in Singapore covers bags, power cuts and pumping at work, and the milk feeding calculator estimates how much to put in each bottle.

Frequently asked questions

What does expressing mean in breastfeeding?

It means removing milk from your breasts yourself, by hand or with a pump, instead of your baby drinking it straight from the breast. The milk is then fed to your baby or stored.

Is pumping the same as expressing?

Yes. Pumping is expressing with a manual or electric breast pump. Hand expressing is the same job done with your fingers.

How often should I pump breast milk?

To build supply without breastfeeding, SGH advises 8 to 12 times in 24 hours, including at night. At work, HealthHub suggests about every three hours.

How long can expressed milk stay out in Singapore?

HealthHub says 4 hours at a room temperature of 25 degrees C. If your room is warmer, chill the milk sooner, or put it in a cooler bag with an ice pack, which HealthHub allows 24 hours.

Related terms

• Let-down Reflex: The reflex that makes your stored milk flow when your baby sucks. Some mums feel a tingle, others feel nothing.
• Engorgement: Breasts that are overfull, hard and painful, most often in the first days after birth as your milk comes in.
• Mastitis: A painful, inflamed patch of breast, often infected, with fever and chills. Common in the first months of breastfeeding.
• Lactation Consultant (IBCLC): A breastfeeding specialist; IBCLC is the international credential. Helps with latch, pain, supply and pumping.
• Colostrum: The thick yellow first milk your body makes in the first few days after birth.
• Latch: How your baby attaches to the breast to feed. A deep latch takes in the areola as well as the nipple.

See every term in the glossary