Sometime last week I got into a discussion about molds being found in breast pumps and although there has yet to be any documented (in my knowledge) cases in SEA on this, several lactation professionals (and some medical professionals) had actually found them in breast pumps and the shocking part is that, they are found mostly in the most well loved Medela Pump In Style.

How is it that the beloved breast pump of majority of mothers is associated with cultivating colonies of green/black molds? Now I do not own a PIS nor has had a chance to use it, however, the PIS has an open system which is prompt to mold. Since the open system does not contain a barrier between the milk collection kit and the pump mechanism, milk is exposed to the outside air, which is drawn through the pump system. This allows any impurities that may be found in the air such as dust, smoke, pet dander, airborne bacteria, and viruses to contaminate your breast milk.

There is also the possibility that milk particles can be sucked into the pump’s tubing, as well as the parts of the pump that cannot be cleaned. If milk particles in the tubing go unnoticed, mold can begin to develop in the tubes, as well as the pump motor. This may come as a surprise as I’ve been told by a number of people that Medela was one of the few pumping systems with a closed system.  That’s why it’s not supposed to be a problem to buy one used and then just replace the tubing, however, this true for the very expensive hospital grade pumps but not the personal ones we see in stores.

Open collection systems allow for more flow of air/suction and may be more effective for most women. These systems can compensate better for different tissue elasticities and sizes and shape of the breast. When an open collection system is used, the pump’s suction can cause milk to overflow it into the collection system tubing, which may lead to milk particles being drawn into the pump motor. If milk leaks into the pump’s tubing, the tubes should be washed, sterilized and air-dried prior to using the pump again. Failure to thoroughly clean collection tubing may lead to mold growth within the tubing. Some models of pumps have bacteria and overflow filters which prevent milk from entering the tubing.

A subtype of the open collection system is the single user suction source. These type of pumps have added hygienic benefit of all the parts that generate the suction or come in contact with breast milk stay with the mother. The parts that generate the suction are external to the pump, can be removed, providing outstanding protection against cross contamination. These pumps are rental or hospital grade breast pumps. Using a pump of this type virtually eliminates the chance of cross contamination of the pump from mother to mother.

The diaphragm in a closed system eliminates the possibility of milk being able to overflow into the pump tubing. Because milk is unable to be exposed to the pump motor, closed collection systems are marketed as more hygienic than open collection systems. It is important to clean the diaphragm as condensation or milk may reach this part causing bacterial contamination. If the diaphragm is contaminated this may defeat the purpose of the closed system. The barrier in a closed collection system breast pump is marketed as preventing outside air from contaminating the expressed breastmilk in the collection bottle, which preserves the milk’s purity. The diaphragm may limit the amount of air/suction that can be used to extract milk from the breast. It may also not be able to compensate for larger shield sizes as well. There are no studies comparing the open versus closed system design. Most information is marketing materials without studies to back them up.

So for mothers who are thinking about getting a second hand breast-pump, they should consider these factors. Medela and most of other breast pump companies have indications about the pump’s suitability for multiple users like the one mentioned here for Medela Lactina. The amount up front for a good pump like the PIS may seem daunting to some mothers, however, I would advise against the idea of sharing breast pumps for hygiene purposes. In one case, the mother was treated for repeated episodes of thrush, however her physical examination results shows that there is nothing under the maternal health section to be concerned off. A second evaluation was then performed, but this time it was on the breast pump that she was using. It was none other than the Pump In Style. After some discussion, the pump was a second hand unit bought from a friend at a cheaper price and when the pump was taken apart, there were molds growing all over. I would think that any action to take apart the unit would definitely void the warranty of the unit.

This in fact has got me thinking about my Avent IQ ISI Uno which I had stopped using some 1.5years ago. I wonder if I were to take apart the motor, would I be able to find myself with a pateri dish of mold? The last I had used it was in April 2009 and I had made sure to wash the parts thoroughly and sterilize them, however, I am unable to do likewise for the motor except to clean the crevices with a cotton bud soaked with water. The contents up to this part was typed while I was away from home and now that I have my little one occupied with her Daddy, I had sometime to dig out my old breast pump and the pictures below confirmed my suspicion :

Underneath the motor


See the yellow stained crevices?


A closer view.


For certain, milk could not get to the handle during expression. However, the mold has found its way to cultivate itself there too


It has even managed to grow in between the motor parts


Even the power outlet was not spared. Can you see the little black specs of "dirt"? They are in fact mold.


The inner part of the pump where during expression the white plastic knob in the middle will rise and the milk can even be collected here.


This pump had costed me close to $350 at the time of purchase (in 2008) and it was a very good pump (at least to me after disagreeing with the Medela Mini). Given on any average day, this trusty pump would give me close to 15-18 ounce in an 8 hour time frame, however this indication is not to be construde of how much milk I am actually producing as the mechanism is totally different compare to the compression of a baby’s mouth.

I loved this pump very much and I was hoping that it could be used subsequently for my next babies, however upon seeing the condition of the pump now, I have decided otherwise. So ladies, if you are thinking about getting a second hand pump or sharing it with your friend or sister, please reconsider this option and for those who already have a breast pump or had put them away, take a closer look at the parts of your pump, you might unintentionally be cultivating a colony of mold in there.


6 Responses to “Molds in my breast pump! But how can that be?”

  1. Hayati Hamidon says:

    moe!!so scary!!thank god for manual pumps!!

  2. Ness says:


  3. Jat says:

    ewwwwwwwwwwww how to prevent this??? how wud u recommend i keep my avent motor clean?? i’m so paranoid now!!!!

  4. Didi says:

    I use Medela Swing and there’s a small faded black dot in the tubing..I’ve cleaned and sterilised it soooo many times but it won’t go away! Should I just give up and buy a new tube? Or am I fussing over nothing?

  5. Dot Dot says:

    Jat, honestly, I am really clueless myself as there is no way to actually open the entire pump motor head and clean it or to prevent any milk sprays from actually getting into it. I guess we just have to be vigilant and clean the pump as often as we can or another alternative would be to choose to use a WHO standard breastpump or the ones that do not have possibility of a back flow.

  6. Dot Dot says:

    Didi, I’m not really familiar with the Medela Swing, but a friend of mine who uses it has to wash the tubing every time she uses the pump and she will run the motor with the pump attached to it just to dry the tube. I’m guessing that mold would be able to be cleaned after numerous times of washing but there is also a possibility of it being embedded in the structure of the tube.

    In my personal choice, I would get a new tube

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