Expressing with a pump

Expressing your breast milk

Choose the right funnel size

There are 2 funnel sizes available, 26mm and 31mm.

To make sure you have the right size funnel for you, place the shield on your breast with the nipple in the centre.

  • When the pump is switched on, the nipple should not rub against the sides of the shield. If it does, the funnel is too small.
  • Only a small amount of breast tissue should enter the funnel. If a lot of breast tissue enters the funnel, the funnel is too big.

A nurse or midwife can help you check if you have the right funnel size.

Getting started

  • Hygiene is important. Clean the pump using a Clinell wipe and then wash your hands.
  • Attach a sterile bottle to the expressing kit to collect the milk.
  • Before pumping, massage your breast for 2 to 3 minutes to stimulate your milk supply. Be gentle and make sure you stimulate the nipple.
  • Put the expressing kit tube into one of the holes on the front of the pump. If double pumping, use 2 kits and put 1 into each hole.

Using the pump

  • Fit the shield to your breast and press the 'on' button.
  • The pump starts in ‘stimulation’ mode. The top line of the screen is orange in this mode. The cycles are quite fast but also gentle. This lasts for 2 minutes.
  • The pump then switches to ‘expression’ mode. In expression mode, use the down arrow marked 'cycles' to turn the cycles down low. Use the up arrow marked 'vacuum' to increase the suction (sucking air effect) to a comfortable level for you. In this mode, the top line is green.
  • When you have finished expressing from one breast, switch the pump off. Move to the other breast and start again.
  • When you have finished expressing, label the bottle. Give it to the nurse or midwife who is caring for you or your baby.
  • Clean the pump again with a Clinell wipe and wash your hands.

How long to express

There is no minimum or maximum amount of time to express.

The stimulation phase on the pump imitates how a baby sucks gently but quickly when they attach at the breast.

You might find that your milk starts to flow during the stimulation phase. Otherwise, you might not see any milk flow until the expression phase starts and you have changed the cycles and vacuum.

Everyone's ‘let down’ happens at a different time. Try not to compare yourself and the amount of milk you produce to others. Continue in expression mode until you see the milk flow slow or stop.

To help increase your milk supply, express from each breast twice.

Cleaning the expressing kits after use

After you have used the expressing kit, it needs to be washed. Please see the guidance in the area where your baby is being cared for, or speak to a member of staff.

Resource number: 4863
Last reviewed: December 2019
Next review: December 2022

Contact us

If you have any questions or concerns about expressing breast milk, contact the team caring for your baby. 

Neonatal Unit

Phone: 020 7188 4045

Breastfeeding team (maternity)

Phone: 020 7188 7564

Postnatal Ward

Phone: 020 7188 5149

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Do you have any comments or concerns about your care?

Contact our Patient Advice and Liaison Service (PALS)

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