Breast Flange Size - How Your Breast Pump Flange Affects Your Milk Supply

One of the most common breastfeeding questions we get is regarding a mom's breast pump.  What breast shield size will work best?  Choosing the correct breast pump flange is even more essential than choosing the correct nursing bra size, although both are important.  The figure below shows what a correct fitment inside your breast pump flange should look like.

It is imperative that there is enough room to draw the nipple into the flange so that the areola is compressed where the lactiferous sinuses are located.  As you can see from the image below, the lactiferous sinuses are located about an inch behind the nipple.  

This is where the majority of the milk pools before milk ejection which is why it is essential to compress the sinuses properly when pumping.  If the flange is too small, the nipple is compressed and not the milk sinuses.  

If the breast shield you received with your breast pump does not fit properly as in the first image, you need to seek out the correct size as soon as possible.  When the nipple is drawn into the flange, there should be adequate room on one or both sides of the nipple.  If not, examine your nipple at rest prior to pumping.  What is the diameter of the nipple?  Using an everyday object like a coin can help you determine diameter.  The image below will offer coin size comparison and tips on how to measure.

If you nipple is the size of a penny or even a nickel, the standard breast shield size that came with your electric breast pump may work for you.  This is because some of the brands offer a slightly larger flange than the most common breast shield size that were included with your Medela or  Spectra breast pumps which is a 24mm breast shield. For example, most Ameda breast pumps include an Ameda 25 mm breast pump flange. Hygeia breast pumps include a Hygeia 27 mm breast pump flange.  ARDO includes a 26mm flange.

But if your nipple fitment looks or feels too tight or if you can visually see that your nipple diameter is larger than a nickel, you will need to purchase a larger breast flange right away.  The following manufacturer's offer custom breast pump flange sizes for your convenience:

Ameda Custom Fit Breast Flanges replace ones in the Hygeinikit, Purely Yours, Ultra, Finesse and Ameda Mya Joy breast pumps have 28.5mm flanges and 30.5mm flanges available as well as 32.5 and 36 mm.
Ameda also offers a 21mm breast flange for Ameda Mya  and Ameda Mya Pro (does not fit Mya Joy),  24mm and 28mm Ameda Mya flanges as well as a 30mm flange.

Hygeia Large 29 mm breast flange and Hygeia X-Large 31 mm breast pump flange

Spectra 28 mm breast shields and Spectra 32 mm breast shields

ARDO 26 mm breast shells and 28-31 mm breast shells (AKA breast shields or breast flanges) and even an XXL ARDO 36 mm breast shell

For brands like Medela or Rumble Tuff, we recommend using Pumpin' Pal Super Shields so that you get the benefit of a better fitment and can avoid back strain due to leaning forward while pumping without an angled breast shield.

What if your breast shield is too large?  Some manufacturers are now offering a smaller flange such as the Spectra 20mm breast shield.  Inserts are also available from several manufacturers to make your breast flange smaller.  If your nipple diameter is the size of a dime or if too much of the areola is being drawn into the breast shield, try an insert.  Ameda offers the Ameda Flexishield which is a 21 mm massaging insert that will fit both Ameda and Medela breast shields.   This silicone massaging insert which actually helps with milk let down. I have seen moms pump an extra ounce of breast milk when using a Flexishield massaging insert.  This is due in part to the correct size for better milk sinus compression, but also because silicone massaging inserts like the Ameda Flexishield massage the areola much like the peristaltic wave of the infant's tongue when the baby is at the breast.  This action tends to assist the let down reflex.  Other breast pump manufacturers such as Hygeia, Rumble Tuff, Medela, and Bailey can be used with the Pumpin' Pal Small and Pumpin' Pal X-Small Super Shields.  The Pumpin' Pal small and x-small Super Shields yield some let down assistance as well due the movement of a flexible silicone breast shield.  

If the manufacturer of your breast pump doesn't offer the size you need, standard breast flange inserts are also an option.

Buying the correct size breast flange is as essential for milk supply as changing your valves, diaphragms or filters on your breast pump to maintain proper suction.  In addition, if the breast flange is uncomfortable, moms tend to pump less and wean sooner.  Here's to hoping this information impowers you to keep on breastfeeding and pumping!

Happy Pumping!

Tanya