How to Master Breast Pump Flange Fit

Proper fit is always important, and that’s especially true when it comes to breast pump flanges aka breast shields. Lactating parents who have breast pump flanges that are too small or too large can experience soreness, irritation, and even clogged milk ducts. Meanwhile, flanges that are the proper size are more comfortable when pumping and generally yield more pumped milk. 

First things first — what is a flange? 

Flanges or breast shields are the cone-shaped plastic or silicone pieces of a breast pump, worn over your nipples to create a gentle vacuum for breast milk extraction. These come in a range of sizes. In order to ensure the right breast pump flange fit, an International Board Certified Lactation Consultant (IBCLC) may measure the diameter or ask you questions about any discomfort while pumping.  

How can you tell if your flange is too small? 

Flanges that are too small may cause excess friction, pinching, or squeezing as the nipple is pulled against it. As a result, your nipple or areola could become white or discolored, and you could experience lower pumped volume, plugged ducts, and damaged, sore nipples. 

And how can you tell if your flange size is too big? 

If your flanges are too large, your areola will be pulled into your pump’s breast flange tunnel, which can cause discomfort, as well. It’s also possible that your areola won’t receive enough stimulation, which could cause lower pumped volume and sore nipples. 

So how should a breast pump flange fit? 

A flange that’s the correct size will allow your nipple to fit centered in the flange’s narrow tunnel, without any uncomfortable rubbing against the side of the tunnel walls. Other signs that you have the correct flange include: your areola does not get sucked up into the tunnel of the breast pump; after pumping, there is no remaining milk in parts of your breast (which could indicate uneven extraction); and you don’t experience nipple pain or discoloration. 
 
Also be aware that it’s common for your nipple size to change throughout your breastfeeding journey, so it’s a good idea to have a small range of flange sizes on hand. 

Talk to your International Board Certified Lactation Consultant (IBCLC) 

Your IBCLC is the expert when it comes to comfortable, effective flanges and breast shield sizing. Ask them to assist you with determining the correct size breast pump flange fit for you. Whether you’re a new parent or a pro, breast pump flange fit can require additional consideration — but it’s one of the most essential components to pumping successfully and sustainably. Remember, you deserve to be comfortable, and the more relaxed you feel while pumping, the better for everyone!