Breast comfort and milk output are good indicators for if you have the right shield or flange size for your breast pump. Correct sizing of your nipples ensures you are able to remove the most amount of milk during your pumping session and be comfortable during and after pumping.
If your flange is too big, it can be uncomfortable or painful as it stretches too much of the areolar tissue, pulling it into the tunnel of your flange. You may have a hard time keeping the flanges from staying suctioned to your breast while the pump is on. Your milk removal will not be effective and can leave you feeling still full and worse, uncomfortable from the wrong fit.
When your flange is too small, it can rub on the sides of your nipple as you pump and cause soreness. A flange that is too small can cut off blood circulation to the nipple and cause blanching of the nipple and sharp pain called a vasospasm. This pain can occur between pumping sessions as well as itching or a burning sensation with continued use of a flange that is too small.
The amount of milk you are able to remove while pumping can be greatly affected if an incorrect flange size is being used. Determining the best pumping flange for your chest is made easier with the help of Legendairy Milk’s Nipple Ruler.
Using your Nipple Ruler tool in front of a mirror will help you see best. Snap a photo or video with your phone to re-watch how you measured your nipple and determine if the ruler was placed well for taking your nipple measurement.
On the Nipple are two ways to measure your nipple - a ruler and a circular guide. Before you begin, you will want to take a look to see where you will be measuring. To get the correct sizing, you want to measure only the nipple and not the areola which is the darker area around the nipple extending out from the base of the nipple. It is ok if your nipple does not protrude. Some parents have flat or inverted nipples and are still able to measure for their correct flange size.
On the long edge of the tool is a millimeter measurement ruler guide to measure the diameter of your nipple.
To measure your nipple using your Nipple Ruler:
Hold the ruler with 0 lined up with the edge of one side of your nipple.
- One the other edge of your nipple is the number in millimeters of your nipple diameter.
- Nipples are not always the same size. Measure each nipple individually since you may not get the same measurement on the left and right sides of your chest.
Using the circles on your silicone measuring tool:
Center a circle close to your nipple diameter over your whole nipple.
- Your nipple should fit completely inside the circle.
- Make sure you can see your entire nipple inside the circle and right where it meets the areolar tissue.
- The number in millimeters indicates your nipple diameter.
- Don’t forget to measure each nipple individually since you may not get the same measurement on the left and right sides of your chest.
Our nipples change in size from the beginning to the end of a pumping session. As you pump, the nipple swells and becomes larger in diameter. Feeding directly at breast and hand expression affect your nipple differently than with using a pump and there is more swelling of the nipple while pumping.(1)
Your nipple measurement may also change over time. Several months into using your breast pump and feeding your baby, it may be necessary to measure each of your nipples again. In one study of mother’s expressing milk for their preterm babies, 77% of the women needed a larger flange size as time went by.(2) A correct fitting flange allows your nipple to move freely in the tunnel of the flange pulling in only a little of the areola.
Breasts and nipples are many different shapes and sizes and pumping is not a one size fits all activity. Finding the right fit for you may mean you need to order flanges that were not included with your pump. Most pumps come with size 24mm and 27mm flanges. If this isn’t the right size for your pumping needs, you can order different size flanges.
Breast tissue elasticity also varies among lactating people. There are inserts that can be placed inside your pump flange to make a more comfortable fit and experience. Having an IBCLC who can guide you through finding the right fit for you may be helpful if you are having a tricky time getting that comfy and most effective flange fit.
If you measure your nipples before beginning to pump or before you have your baby, you will want to add 1-2 mm to the measurement you found for your nipple diameter for choosing the correct flange size. This will allow for the amount of swelling that occurs during pumping.
The silicone tool is more comfortable to use than hard plastic tools. It is more stable than a paper ruler and is super soft against your skin helping to mold it to your uniquely shaped breast for more accurate measuring. Wash your measuring tool with warm soapy water before and after each use.
- Francis, J., & Dickton, D. (2019). Physical analysis of the breast after direct breastfeeding compared with hand or pump expression: A randomized clinical trial. Breastfeeding Medicine, 14(10), 705-711.
- Meier et al, Choosing a correctly-fitted breast shield for milk expression. Medela Messenger. 2004;21:8-9
Francis, J., & Dickton, D. (2019). Physical analysis of the breast after direct breastfeeding compared with hand or pump expression: A randomized clinical trial. Breastfeeding Medicine, 14(10), 705-711.
Meier et al, Choosing a correctly-fitted breast shield for milk expression. Medela Messenger. 2004;21:8-9
Wambach and Spencer, Breastfeeding and Human Lactation 6th edition, 2021; 375