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.

What Happens If My Flange Is Too Big Or Too Small?

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.

How Do I Find My Flange Size?

A lactation consultant can help ensure that your flanges fit properly. If you are local to My Pure Delivery, we offer 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. If you still feel as if you are not using the right sized flange, or are not getting adequate milk volume, you may want to try using your exact measurement, without adding 2-3mm. 

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!