June 12, 2023 3 min read

Pumping is something that most new mothers think will be an “easy” part of breastfeeding. Buy the pump, attach it to the breast and viola! - milk will be flowing in seconds! But once you open the box and realise just how many parts there are to connect it can be a bit overwhelming and make you realise just how many elements play a role in a pain free, successful pumping journey - the most important being the flange size.

The flange breast and nipple, forming a vacuum seal with the areola. It’s shaped like a funnel.

It is a necessary part of the pump because it draws your nipple into the tunnel of the pump where milk is extracted from. The flange also helps to create necessary suction to extract milk by forming a seal. Flanges come in different sizes as well as different materials, (plastic, silicone and even glass) depending on which pump brand you buy. Most pumps come with a standard size flange, so it will be up to you to make sure you have the correct fit and if it is not you will need to buy the size that fits your breast comfortably. If you are lucky, the one that came with the pump will fit you from the start - but how do you know what is the “correct” fit of your flange?

 You can use the FREE downloadable Nipple Measuring Tool on our Mrs Milk website to discern which flange size would be best for you --> Mrs Milk Nipple Measuring Tool

Even if you’ve measured everything perfectly, the final answer to knowing if you’ve found the right flange is going to come when you place it on your breast.

A flange fits correctly when: 
  • Your nipple is centered in the tube
  • No parts of your nipple rub against the sides (you don’t want any friction once you start pumping)
  • Little or no areola is pulled in when the pump is turned on
Signs that a flange is not fitting properly when:
  • You experience nipple pain during or after the pumping session
  • You notice your nipple is becoming discoloured, chapped, or otherwise injured

A pump that is suctioning your breast correctly will mimic how a baby would suck. Your nipple needs to be able to move in and out of the flange’s tunnel to do this.

If your nipple can’t complete this movement easily, it’s going to be injured by friction when the suction is turned on, and the pain is only going to get worse each time you pump.

In addition to breast and nipple pain, using the wrong sized pump flange can negatively impact the amount of milk you are able to get out of your breast.

  • A flange that fits too tightly will cause the breast to be constricted in ways that can lead to clogged or blocked milk ducts. (When ducts are clogged, they don’t release milk and new milk isn’t formed as quickly which can lead to a drop in milk supply)
  • A flange that fits too loosely won’t provide adequate suction. This can also lead to milk being left in the breast and lower milk production in the future. Pain and infection can develop from this as well (Mastitis is something no women wants - ouch!)

You’re not alone if you discover that finding the perfect flange for your breasts isn’t easy. If you’re having trouble finding the right fit, a lactation consultant might be able to offer some further assistance. In the mean time, be patient and gentle with yourself. You are doing a GREAT job!