Why Flange Size Matters + How To Find Your Size

Some moms pump out of necessity, others pump to build a freezer stash or to donate their milk to babies in need. No matter why a mom is using a pump, it is critical that she is using a pump with flanges (the plastic funnel-shaped pieces that fit over the breast and nipple) that are properly sized for her. Improperly fitting flanges are a very common problem among pumping moms. In fact, one of our lactation consultants estimates that over ninety percent of the pumping moms that she sees are using the wrong sized pump flange. If a pumping mom is experiencing pain or reduced amount of milk output, poor flange fit may be to blame.

Flange fit is based on the width of the nipple itself, not the size of the areola or the breast. To ensure that your flange fits properly, there should be a small amount of space all around the nipple when the flange is placed against the skin and the nipple should be able to move freely within the flange when the pump is turned on. If the 

nipple rubs against the inside of the flange, or if part of the nipple blanches white from being compressed by the flange, then the flange is too small. Other signs that the flange is too small may also include bruising of the nipple, the nipple turning red or even blue, or a white ring around the base of the nipple.

For some women, a small amount of areola may enter the flange during pumping even when the flange fits properly, however, an excess amount of the areola being drawn into the flange is a sign that the flange is too large. Flanges that are too large may also result in the nipple being pulled all the way in to the end of the flange, which can cause pain. Physical signs that the flanges are too large may also include a full circle ring all the way around on the skin outside of the areola. Flanges that are too large or too small can make pumping inefficient by not removing the optimal amount of milk during each pumping session, which can have a negative effect on the overall milk supply.

It’s also important to note that it’s common for a mom to need different size flanges at different times over the course of her pumping journey. There are many reasons for this, and most of them have to do with the many, many changes that your body goes through after pregnancy and delivery. Our lactation consultants recommend determining your proper flange size at delivery, and then checking again after about two weeks.

A lactation consultant can help ensure that your flanges fit properly. If you are local to My Pure Delivery, we offer free pump consultations that include flange fitting. If you are not local, or want to measure on your own, MayMom has a great printable measuring tool. When measuring yourself on your own, remember to pump for at least five minutes (or if you are still pregnant, add 5 mm to your measurement). To determine your correct flange size, add 2-3 mm to the number that you got when you measured. 

An ideally sized pump flange can help decrease discomfort and ensures that the ideal amount of milk is expressed, which can help your freezer stash and your milk supply. 

Happy pumping!