Size does matter....but bigger is not always better

“Your flange should fit your nipple like a shoe”


Let’s talk flange sizing – it is something that could make or break your expressing journey.


I was told to start expressing for my daughter when she was 3 days old by an IBCLC.  My milk hadn’t come in and it looked like she had lost too much weight.  I was initially told that I needed 27mm flanges.  A week later I went for a follow up appointment and was told that I needed 30mm flanges.  By now I was barely expressing 10-20mls/session.  Slowly it increased to about 30mls/session but would not increase any further.  Using the 30mm flanges hurt and I kept going back to the 24mm flanges that I had.  I would also get more out with the 24’s (only about 10mls more and no more than 30mls total).  Around 6 weeks post birth I saw a different IBCLC who wanted to help me increase my supply and suggested I try a different brand of breast pump while I waited for my Spectra to arrive.  And she suggested that I try 36mm flanges.  In between all this another IBCLC had agreed that 30mm flanges seemed to be correct.


I tried the 36mm flanges but quickly went back to the 24mm’s – they were definitely more comfortable and I got more with them.


About 2 weeks before I ordered my Spectra I had tried a friends electric pump (a brand that you can buy off the shelves in Big W or Target) which had ‘comfort massaging inserts’ – I got the most I had ever got – 40mls!  When another friend told me about the Spectra I had ordered it with their ‘massaging inserts’.


I also joined an Exclusive Expressing Facebook group on her recommendation.  After a week or so I posted my story, desperately wanting to increase my supply.  The main thing I was told was to increase the number of sessions I was doing (I was only doing 6/day whereas the minimum is 8).  But someone in there also recommended checking my flange size.  I didn’t pay too much notice to that suggestion has I was now using the Spectra 24mm’s with the inserts (which took them down to a 22mm) and it was somewhat comfortable and I was seeing an increase.


Over the next 8mths of exclusive expressing (I did my last session 3 days before my daughter was 10mths old) I saw numerous posts about flange sizing.  And I came to realise just how important it was to get the correct size and that unfortunately those 3 IBCLC’s who had told me I was a 30-36mm were wrong.


In March 2016 I started selling Spectra breast pumps as an authorized stockist.  Flange sizing quickly became a ‘passion’ of mine (some might say obsession!).  I realized that so many new mothers were being told the same thing as me – you need a 27, 30 or 36mm flange. 


I started stocking Maymom flanges around the same time as the Spectras and I did a survey on the Exclusive Expressing group to work out what volume of stock I should be ordering.  Most said they were between a 19 and 27mm flange, so that is mainly what I stocked.  Over time I realized I was selling more 19mm’s than anything else and I was getting numerous requests for 17’s and even 15’s.


A fellow IBCLC who I know went through similar expressing journey to me (she is in the Exclusive Expressing group) did a similar survey to me just recently and interestingly the vast majority said they were a 17, 19 or 21mm.


I have also seen numerous clients who have been told to use flanges that are too big for them with damage (usually around the areola or base of the nipple) and poor output.  The vast majority of the time they say that using smaller flanges (ie ones that fit properly) are more comfortable and help them yield more milk.


I quickly realized that the rule ‘measure the diameter of your nipple* before expressing and add 4mm’ worked the majority of the time.  Although now days I can just look and judge their size.



*JUST your nipple - not the areola.  In case you do not know - your areola is the darker coloured skin on your breast, your nipple is the part that extrudes from that.  If you have flat or inverted nipples - they are often more sensitive than your areola and can sometimes be stimulated to stick out by rubbing on them slightly


Every day I get multiple texts, calls, and emails asking about flanges.  Some what help figuring out their sizing, some want to know if I stock 30, 32 or 36mm flanges.  When I get those requests for 30mm+ flanges I send them my sizing guide and recommend that they double check their sizing.  Inevitably I get a response along the lines of ‘the midwives in the hospital said I’m a 30mm’, or ‘the 24/27mm was hurting so I was told to go bigger’.   I have also had numerous follow up messages along the lines of ‘this size is so much more comfortable’ and/or ‘I’m getting so much more with this smaller size flange’.


Here is another graphic to help you know where to measure.


In the 4 years I have been doing this I have seen only 2 mothers who truly needed 30+mm flanges – and I have seen hundreds, if not over a thousand, nipples – please trust me when I say that bigger is not always better, especially in this case.  And I am saying this not to confuse you or to criticize other health professionals – please keep in mind that breast pump flange sizing is not a part of the midwifery training, or even the lactation consultant training. 


Of course, there are always exceptions to rules and it might take some trial and error – but in my experience the exceptions are rare and this is a good starting point. 


If you need help with flange sizing you are welcome to see me in person (in Perth) or send me a video of you using your current size - there is no charge for this.  Send me a text or email - 0405427998 or