Updating Breast Shields for Today's Moms: Introducing PersonalFit Flex

Jenny Murray, BSN, RN / June 2020

Breastfeeding initiation rates have significantly improved over the years, which tells us that mothers want to breastfeed. If a mother does have to (breast) pump regardless of the reason, such as a premature birth or going back to work, comfort and milk supply play a major role in continuation rates.¹׳²׳³ 

Pump technology has consistently changed throughout the years. The pump, though, is only one piece of the puzzle, right? What about breast shields?

Dr. Danielle Prime, a lactation scientist out of Western Australia, realized that although breast pump technology has improved throughout the years, it has been over 50 years since anyone looked at the breast shield.

What could be done to improve the breast shield? Could comfort be improved? Could milk supply be improved? 

To clarify, the parts of a breast shield are:

1. Tunnel - About the fit of the nipple.

2. Flange - The cone shape that rests on the breast.

The Research

Dr. Prime and colleagues utilized 3D scans to study the wide array of contours and shapes of the lactating breast. They discovered that the current 90-degree angle could be restrictive for some mothers. This guided their research into studying different angles of the breast shield. More than 100 mothers were involved in 4 different clinical trials. The new breast shield was used in over 1,000 pumping sessions.⁴׳⁵

What Changed?

  • The Angle

    Breast shields are currently designed at a 90-degree angle. Dr. Prime and colleagues researched different angles and found that a 105-degree angle optimized comfort and milk volume. 

    With the current 90-degree angle, it could be difficult to tell if the nipple was centered inside the tunnel prior to pumping. The new 105-degree angle allows the nipple to rest inside the tunnel, which improves visualization of the correct placement prior to pumping. This angle also allows for contact with the breast tissue without pressure points or gaping on the breast.  

    The tunnel size did NOT change.
  • The Shape

    The new oval shape (versus the current round shape) allows mom to place the shield according to how it best fits and feels during pumping. This means there is no right or wrong way to position the shield, which allows mom to position herself comfortably without affecting the seal. The addition of the soft rim provides comfort and a great fit.

    As let-down occurs, milk ducts expand up to 68%. This expansion allows for the increased volume of milk flowing through the ducts. Through research, it was determined that milk flowed more freely with the new 105-degree, oval angle shields. This is generally thought to be because the shield shape fits the contour of the breast better, resulting in less compression of the milk ducts - thereby allowing improved milk flow.

What did they determine in clinical trials?⁴׳⁵

1. Mothers reported improved comfort.

2. Mothers who pumped with the 105-degree breast shield expressed 11.8% more milk, per minute.

3. There was significant improvement in the drainage of the breast. 

What is the name of the new breast shield?

PersonalFit Flex™. Currently, Medela offers both the PersonalFit Flex breast shields and the PersonalFit breast shields. 

Remember, sizing is important! When I was practicing at the bedside, I was not confident when it came to correctly sizing breast shields. As a NICU nurse, we were taught how to correctly size a breast shield but because it was not something I practiced on a daily, weekly, or even monthly basis I did not feel I knew the best fit for a mom. Outlined below is a quick reference to help determine appropriate breast shield sizing, which is a critical component to comfort:

Questions to Ask

  • Does mom's nipple move freely inside the tunnel?
  • Is the nipple rubbing the sides of the tunnel?
  • Is the nipple turning white?
  • Do you see any redness?
  • Is there an excessive amount of areola being pulled into the tunnel?
  • Is it painful?
  • Does mom feel completely expressed after pumping?


  • A mother may need a different size shield for each breast.
  • Ensure the mother does not press breast shields into tissue. This could cause compression of the ducts and inhibit free flow of milk. 
  • A mother's nipple size may change once she begins pumping.
  • In the immediate postpartum days, excess fluid can cause edema in the nipples and/or areola. A larger size shield may be needed in the first few days.
  • Tissue elasticity can affect breast shield size.
  • Size of breasts do not determine size of shield.

I've yet to hear a mother say she likes to (breast) pump. What I do know is that we can improve that experience by making the expression of breast milk more comfortable and/or work to ensure mom meets her goal of improved milk production. After all, we know mothers desire to give their infants, especially the compromised neonates, the very best medicine - mother's own milk. 


  1. Rhodes, J.  Improving Delayed Lactogenesis and Suppressed Lactation in At-Risk Mothers White Paper.  2017.
  2. Kent, J., Prime, D., & Garbin, C.  (2012).  Principles for Maintaining or Increasing Breast Milk Production.   Journal of Obstetric, Gynecologic, & Neonatal Nursing, 41, 114-121.  doi: 10.1111/j.1552-6909.2011.01313.x
  3. Odom, E.C., Li, R., Scanlon, K.S., Perrine, C.G., & Grummer-Strawn, L.  Reasons for earlier than desired cessation of breastfeeding.  Pediatrics, 131(3), e726-e732.  doi: 10.1542/peds.2012-1295.
  4. Flex™ technology – a whole new pumping experience.  Retrieved from https://www.medela.com/breastfeeding/flex-breast-pumps/flex-technology-breast-shield
  5. ClinicalTrials.gov [Internet]. Bethesda MD: National Library of Medicine, USA, data on file: NCT02496429; NCT02492139; NCT02719548; NCT03091985 https://clinicaltrials.gov/

Get in touch with our team to learn more about PersonalFit PLUS Breast Shields for your practice.

About the Author

Jenny Murray, BSN, RN, began her career 18 years ago as a neonatal nurse in neonatal intensive care. She has since served in a variety of nursing leadership roles within the NICU. Her experience in those roles has driven her love for education and research, especially educating and supporting clinicians in the advancing, innovative world of neonatology. Jenny currently works as a Clinical NICU Specialist for Medela LLC.

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