Why Your Breast Pump Hurts, and It's Probably the Flange
If pumping hurts, or you are getting less milk than you expected, the flange that came in the box is a likely reason. Most pumps ship with one size, and it does not fit most women. Here is how to tell, and what the research says about getting the fit right.
Photo: BabyBuddha
Your nipples are raw by day three, less is coming out than you expected, and you start to wonder whether the problem is your supply. Often it is neither your supply nor you. The plastic funnel that sits against the breast while you pump, called a flange or breast shield, comes in one standard size in most boxes, and that size does not fit most bodies.
Mothers Pumped a Week With Each Size, and the Smaller Fit Won
L.A. Anders, J. Mesite Frem and T.P. McCoy set out to test something they say no study had tested before: whether the method used to size a flange changes what happens when a mother pumps. Their paper, Flange Size Matters: A Comparative Pilot Study of the Flange FITS Guide Versus Traditional Sizing Methods, was published in 2025 in the Journal of Human Lactation, the journal of the International Lactation Consultant Association.
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