If you're pumping breast milk, it's important to use the correct breast shield while you're pumping. A correctly fitting breast shield, or flange, will allow you to pump the maximum amount of milk with the least amount of discomfort.
Mothers who are pumping breast milk for their preemies should be especially careful to make sure that they are using the right size breast shield. Premature babies are often born too small to breastfeed, and Mom must establish and maintain her milk supply using a breast pump. A poorly fitting breast shield can cause:
- Nipple pain or soreness
- Reduced milk supply
- Plugged milk ducts
- Mastitis
How To Tell If Your Breast Shield Is the Right Size
If your breast shield is the right size, your nipple will fit nicely in the tunnel. When you pump, the sides of your nipple won't rub against the sides of the breast shield's tunnel, and only a small amount of areola (if any) will be drawn into the tunnel.
When choosing a breast shield, remember that the correct size depends entirely on the size of your nipples -- not the size of your breasts themselves.
You May Need a Larger Breast Shield if:
- Your nipple rubs against the sides of the tunnel while you're pumping
- The outside of your nipple is sore after pumping
- You see skin flecks on the inside of the breast shield
You May Need a Smaller Breast Shield if:
- A large amount of areola is drawn into the breast shield while you're pumping
- You cannot get a good seal with your breast shield
If You Need a Different Size Breast Shield
If you feel like you may need a different size breast shield, talk to a lactation consultant at your baby's hospital. A lactation consultant can watch you pump, and can let you know if you need a different size breast shield. If you're renting your pump from the hospital, she should also be able to help you obtain a different breast shield.
If you're not renting a hospital pump, visit the manufacturer's website for the pump you're using. Most manufacturers of breast pumps offer breast shields in different sizes. If you can't order directly from the website, call the customer service line to find out where you can buy replacement breast shields.
Sources:
Meier, P. "Choosing a Correctly-Fitted Breastshield." Accessed on November 10, 2010 from http://www.medelabreastfeedingus.com/tips-and-solutions/13/choosing-a-correctly-fitted-breastshield
Mohrbacher, N and Stock, J. The Breastfeeding Answer Book, 3rd Revised Edition. January, 2003; La Leche League International, Schaumburg, IL.

