What You Need to Know about Breast Pumps

(Content revised 01/2021)
  • Expressing breastmilk allows me to continue breastfeeding my baby when I return to work!
  • Giving expressed breastmilk let me know how much my baby is drinking.
  • Giving my baby expressed breastmilk save more time than direct breastfeeding!
  • My preterm baby is too weak to suckle on my breast. I need to feed him with expressed breastmilk.

As a new mum, you may wonder when to use a breast pump.

What do you need to pay attention to when using a breast pump?

If you want to know when to express milk, you can read Chapter 5 of Love, Starts from Breastfeeding…This booklet focuses on how to use a breast pump properly.

How a breast pump works

A breast pump extracts breastmilk by creating negative pressure within the breast shield. The basic structure of a breast pump has 3 detachable components.

  1. Breast shield: A cone-shaped cup that fits over the breast
  2. Pump: Creates negative pressure to extract breastmilk; it can be connected to the breast shield directly or with tubing.
  3. Milk container

Please note: You can express milk by hand or with a breast pump. Even if you prefer to use a pump, you should also learn how to hand-express breastmilk in case you need to.

Choose a suitable pump

There are various types of breast pumps available on the market, including manual, electric and battery-powered. There are also single shielded and double shielded breast pumps; the latter can extract milk from both breasts at the same time. Each varies in price, quality and efficiency. You should consider your own needs and choose a breast pump that suits you best. When choosing a breast pump, consider the following:

  1. Operation:
    • Electric double shielded breast pump is suitable for regular and frequent use.
    • Battery-operated breast pump is more suitable for mothers who cannot use the pump in a fixed location or where there is no electric socket.
    • The level of noise during operation varies.
  2. System design:
    Open system Closed system
    Most breast pumps available for sale are of this type. Most breast pumps for rent are of this type, such as those used in hospitals, and Maternal and Child Health Centres.
    The system may allow the breastmilk to come into contact with and be retained in the pump. Shared use of the pump may lead to cross-infection among users. The system has a barrier between the milk and the pump, and hence, it can decrease the risk of contamination and cross infection.
    Only suitable for personal use. Suitable for multiple users. (Each user should have their own set of clean accessories that includes breast shields and tubing.)

    Please refer to the breast pump instruction manual for details.

  3. Choice of parts:
    • Some models have a selection of breast shield sizes.
    • Choose parts that are durable and easy to replace.

Please note: Sharing or using a second-hand open system breast pump has potential risks.

How to choose a suitable breast shield to fit your nipple size

Measure the diameter of your nipple and size of the tunnel of the breast shield; the tunnel size should be 3 to 4 mm larger than your nipple.

Perform a quick test to determine whether the breast shield fits well:

  1. Position the breast shield properly (see page 7 for details).
  2. Adjust the breast pump to the maximum suction level without causing you pain or discomfort.
  3. If the breast shield is properly-fitted:
    • The breast shield has a good seal.
    • The nipple does not rub against the side of the tunnel when being pulled in.
    • None, or very little of the areola, is pulled into the tunnel.
    • You should not feel pain.
    • Your breast will gradually become soft.

The breast shield is too big: too much areola is pulled into the tunnel during pumping which reduces pumping efficiency.

The breast shield is too small: the nipple will rub against the side of the tunnel during pumping; you may feel pain or even bleed.

Correct steps for using breast pump

  1. Preparation: Read the breast pump operation manual carefully.
  2. Steps for using breast pump:
    1. Wash your hands before pumping.
    2. Assemble the clean breast shield, milk container, tubing and breast pump correctly.
    3. Stimulate the let-down reflex to help the milk flow, please read Chapter 4 of Love, Starts from Breastfeeding... 
    4. Centre the breast shield over your nipple and press gently to make a good seal.
    5. Turn the pump on and start at low intensity. Slowly adjust the intensity until milk flows, without causing pain.
    6. Clean the breast shield and any parts that come into contact with breastmilk every time after use. Follow the recommended method of cleaning in the breast pump manual.

Please note: You should not feel any pain when pumping. If you do, first check the size and the position of the breast shields, and the suction force used. If you have further questions, please seek advice from a healthcare professional.

The frequency and duration of pumping

The frequency and duration of pumping vary from mother to mother. In general:

  • During the first 2 weeks after delivery, if you feed your baby with expressed breastmilk only, then you have to pump at least 8 times a day, including at least once at night.
    • After 2 weeks, or when your milk production becomes stable, the frequency of pumping can be reduced to around 6 times daily, avoiding long gaps of more than 6 hours in between each pumping. However, the frequency might vary according to the age of your baby and individual situation.
  • When a single breast pump is used, change to the other breast when the milk flow slows down. Keep swapping, for several times. The total pumping time takes about 20 to 30 minutes.
  • When a double shielded breast pump is used, it takes about 15 to 20 minutes. If the milk flow slows, you can massage your breasts gently.

Please note: In the early days, when milk production is low, or if the milk stops flowing during pumping, you can pause for a while, gently massage your breasts and try pumping again for 1 to 2 minutes. If there is no milk flow, then you can stop. You need to continue to pump once every 3 hours and may gradually lengthen the duration for each pumping session.

Cleaning the breast pump parts

Rinse the breast shield(s) and other parts soon after pumping. Cleanse the grease on the breast shield(s) with detergent and warm water, then rinse with hot water at least twice. Place the cleaned parts in a clean container with cover. Also, disinfect the parts once a day. For details, please refer to the Guide to Bottle Feeding booklet

Please note: If your baby is hospitalised, or if the breast pump parts are shared, then you must disinfect the breast shields and other parts every time after pumping.

Common mistakes when using breast pumps

Mistakes Consequences
Tunnel of the breast shield is smaller than the nipple The nipples become sore or even bleed during pumping
The nipple is positioned to the side of the breast shield
The shield is cupped too hard on the breast Blocked ducts
Excessive suction applied and ignoring the pain for long periods Damage to breast tissue
Hand-expression of Breastmilk Using a breast pump
  • Costs no money
  • Can be done anytime and anywhere without the need for special tools or electricity
  • Requires more skills: the right amount of pressure must be applied to the correct areas
  • Saves effort
  • Costs money
  • Produces noise
  • Attention has to be paid to the process of pumping, size of the breast shield and after care

When your breastmilk has not yet “come in”, or is in low supply for the first 2 days, hand-expression is usually more effective. When the breasts are full, however, using a breast pump saves effort and is likely to be more effective. Some mothers combine both methods by using the breast pump first until the breast is soft and then hand express the remaining milk.

Each has its own merits!


  1. Q: 1. Why bother with direct breastfeeding when pumping is so convenient?

    A: The benefits of breastfeeding for both mum and baby are not limited to the ingredients of the breastmilk:

    • Suckling at your breasts allows your baby to take the lead in feeding. It can prevent overfeeding and reduce the risk of obesity and diabetes.
    • Intimate skin contact and communication during breastfeeding can improve mother-child bonding. It also helps your baby's brain development, emotional and social skills.
    • Suckling at the breasts helps your baby's jaw, tongue and facial muscle development.
    • When you have blocked ducts or mastitis (breast infection), effective suckling by your baby is the best way to clear the blockage.
    • Bottle feeding increases the risk of middle ear infection.
  2. Q: 2. Direct breastfeeding and pumping, which is more effective in providing breastmilk?

    A: It depends. The effectiveness of extracting milk depends on the baby's ability to suckle and whether the method is correct or mother's pumping skills; either can be effective. If your baby does not suckle well, you can use the breast pump as a temporary measure to increase milk production while you seek professional advice. As your baby's suckling improves, you can then gradually reduce pumping.

  3. Q: 3. Should I “empty” my breast using the breast pump immediately after direct breastfeeding?

    A: If your baby's suckling is effective, the amount of milk produced should be optimal. Pumping immediately after breastfeeding may over-stimulate milk production, resulting in an increased risk of breast engorgement, blocked ducts and other problems. Unless suckling is ineffective, additional pumping is unnecessary. If you do not know whether your baby's suckling is effective, you can read Chapter 4 of Love, Starts from Breastfeeding... and also seek help from the Maternal and Child Health Centre, or other healthcare professionals. Actually, your breasts will keep producing milk, so it is impossible to literally “empty” the breasts!

    Watch Video: http://s.fhs.gov.hk/m2ypj

  4. Q: 4. My breasts become engorged quickly after I've just breastfed. Should I pump out the milk to relieve my discomfort?

    A: Usually you will feel fullness in your breasts when it's time to feed. If your breasts are engorged soon after feeding, that can mean oversupply of milk. It is fine to express a small amount of breastmilk to relieve discomfort, but you should seek advice from a healthcare professional to manage oversupply.

    There are other features of oversupply of breastmilk:

    • The breasts are so engorged that it is difficult for your baby to attach well
    • Your baby may choke when put on the breast as the milk flow is too fast
    • Your baby may pass watery stool
    • You may have recurrent blocked ducts
  5. Q: 5. Some mothers want to push themselves to produce more milk in order to reach a target amount that compares well with other mothers, so called “chasing after” milk. Is this necessary?

    A: The appropriate amount of milk depends on your baby's needs. You should judge whether your baby has been fed enough based on the baby's signs of satisfaction after feeding, poo and pee, and weight gain.

    Some mothers think they do not produce enough milk because the amount of breastmilk expressed is less than others; or is less than the recommended consumption stated on the labels of formula milk cans. They may consider themselves to have “insufficient milk” and start worrying about the need to produce more milk. In fact, both the quality and quantity of breastmilk change according to the needs of your baby at different stages. You shouldn't blindly increase the frequency or duration of milk pumping.

    If you suspect you are not producing enough milk, you should seek help from a healthcare professional.

  6. Q: 6. My baby can drink 3 ounces of milk in a feed, but I can only pump 2 ounces at a time. Am I producing enough milk?

    A: The amount of milk expressed each time depends on many factors and is not necessarily the same as the amount of milk your baby needs each feed. Furthermore, if your baby is bottle-fed, the amount drinks tends to be more than needed. If you suspect you are not producing enough milk, you should seek help from a healthcare professional.

  7. Q: 7. Can I pump more milk if I lengthen the duration of each pumping time to 60 minutes or more so that I can reduce the frequency of pumping?

    A: Most of the breastmilk is extracted in the first 8 to 10 minutes of pumping. Extending the duration of pumping does not significantly increase the yield. Actually, frequent pumping is more effective in stimulating milk production.

  8. Q: 8. Can more milk be pumped out if I apply pressure on the breasts while pumping?

    A: Studies show that applying appropriate pressure on the breast increases milk production for some mothers. However, if excessive pressure is applied, or the edge of the breast shields is pressed too hard on the breasts, it will result in blocked ducts and even damage the breast tissue. If milk flow is smooth during pumping, you can relax and need not apply pressure on your breasts.

  9. Q: 9. My breast is full or engorged, yet no milk is being pumped out. Why is it so?

    A: First, you should check whether the breast pump parts are connected properly. If you are anxious, in physical discomfort or pain, the milk let-down reflex can be suppressed and impede milk flow. Try to relax and practise “Prelude to breastfeeding” (see Chapter 4 in Love, Starts from Breastfeeding...), or take painkillers if necessary. You can also try to hand-express milk or pump the other breast while your baby is suckling.

    Please note: Continued engorgement of your breasts may lead to mastitis. If this lasts for more than 24 hours, seek help from a healthcare professional immediately.

  10. Q: 10. Can I alter a single pump to a double pump myself?

    A: This has potential risks as the pump may not operate well if they are connected improperly to the tubing and the breast shields.

Family Health Service

Website: www.fhs.gov.hk

24-hour information hotline:2112 9900