Breast shield Sizing Guide – Choose The Right Size Nipple Shield

After pumping, do your breasts still feel full? Does your areola or nipples turn white after or during pumping? Does your nipple rub the breast shield tunnel sides to the point of causing you discomfort? If yes, it is advisable to consider altering your breast shield size.

A breast flange/shield is the breast pump’s funnel attached to a breast, used for drawing the nipple out, designed to create suction that enables milk to flow out of a storage container/bottle. The nipple size is the primary consideration for choosing the right size of your breast shield. You want to empty your breasts efficiently and comfortably, picking the correct breast shield size is the key.

This breast shield sizing guide will give you an insight into how to measure your nipple size accurately and utilize our breast shield sizing guide.

How do I determine my correct breast shield size?

Determining your optimal breast size based on the nipple diameter is the first step in picking a fitting breast shield. Based on your nipple measurement, use the Breast Shield Sizing Guide to pick a fit breast shield. Your skin elasticity and breast tissue can be used to determine your breast shield size and can be used to confirm if your breast shield fits correctly.

How do I measure my nipples’ diameter and size?

Nipple measurements that determine your breast shield size are the nipple diameter or base of nipple width and size. These measurements give the actual nipple base size. Neither your areola nor the size of your breasts matter, only your nipple size. Measure the nipple diameter of both of your nipples. Some people have different nipple diameters. It is advisable to take nipple measurements before pumping to avoid varying results. After pumping, the nipple size may increase. The breast shield that does not fit correctly affect the nipple size after or during breast milk pumping. 

The nipple diameter measurements can be taken by a ruler (paper ruler, finished ruler) or a string.  I recommend you use the nipple ruler as it is illustrative, easy to use, and read. The breast shield size is stated in millimeters. Nipple measurements of sore nipples are considered accurate as the nipples swell after pumping, plus swelling varies in different women.

Breastshield Sizing Guide

Using your nipple measurements, utilize the breast shield sizing guide to determine which breast shield size fits you.

SizeNipple DiameterBreast Shield Size
Small≤ 1.7 cm  0.67 inches2.1 cm  0.83 inches
Medium1.7-2.0 cm  0.67-0.78 inches2.4 cm  0.94 inches
Large2.0 – 2.3 cm  0.78-0.90 inches2.7 cm  1.06 inches
X Large2.3 – 2.6 cm  0.90-1.02 inches3.0 cm  1.18 inches
XX-Large2.6 -3.2 cm  1.02 – 1.26 inches3.6 cm  1.42 inches

If your nipple measures a diameter of 23mm, you should wear a breast shield size of 30 mm. If you have a nipple diameter of 15 mm, a breast shield of 21 mm will fit comfortably.

Most manufacturers produce a breast shield of sizes 21, 24, 27, and 30 mm.

Looking for Maternity Breastfeeding bra size charts, or Maternity leggings, tanktops? check it here.

How do I test my Flange size?

  • Use the breast pump and correct breast shield size, center the nipple and hold the breast shield gently by your breast. (When pumping, do not press your breasts hard against the breast shield as this will block the breast milk ducts.
  • To get the maximum comfort vacuum level, adjust the pump’s level of vacuum. This will help you achieve the optimum suction level. Turn the vacuum level up, past the maximum comfort level, and later turn down the suction level.

If your nipples move freely and still be centered in the breast shield tunnel during pumping, the breast shield size is correct and you have the correct flange size. 

How do I know if I need to change my breast shield size?

A breast shield size influences the milk output. A correct breast shield size is directly proportional to the maximum milk output. Too big or small breast shield affects the milk output negatively. If you are pumping and experience the following, you need to change my breast shield size:

  • After pumping, your breasts feel full.
  • After and during pumping, the areola or nipple turns white.
  • After and during pumping, a redness develops at the base of the nipples.
  • You notice that an excessive areola is pulled towards the breast shield tunnel.
  • You are feeling discomfort as your nipples are rubbing against the breast shield tunnel sides.

What factors to consider when selecting a suitable Breast Shield?

Below are factors to consider when choosing a correct breast size:

  • Suction level
  • Optimum suction level
  • Level of vacuum
  • Level of suction
  • Comfortable level
  • Vacuum level
  • Maximum comfort level
  • Nipple diameter
  • The elasticity of the breast tissue
  • Breast shield pumping effectiveness

Are you looking for types of breast shield that has a wide range of breast shield sizes?

The series of breast shields at the Philip Avent Nipple Shield and the Medela Baby Care shop has been highly recommended to work effectively. The shop sells both the two-piece breast shield type and in-one breast shield.

Apart from the breast shield, Medela Baby and Philip Avent Nipple Shield online shopping platforms have specialized in baby gear products. They sell household products that you can use to create a safe and baby conducive environment. Apart from selling new-moms favorite products, ordering products from these two online shops is advantageous. They offer access to product support and product warranty coverage.

Find the right breast shield size explained

How to choose the right Medela breast shield size by MedelaInternational


90% of new mums face the challenge of picking the correct breast shield size. Thanks to the breast shield sizing guide, it is a walk in the park to determine which breast shield size fits comfortably.

If you have any questions about the breast shield sizing guide, determining nipple size, and when to change the breast shield size, don’t hesitate to contact us in the comments sections! If you have doubts about any of the content presented in this article, we will be happy to connect you with our lactation consultants.

Our lactation specialist spends hours giving information on breast shield and lactation consultations to new mums. Get the correct contact, for we are always here for you! Our lactation consultant offers to be there for you during your lactation period.

Picture in this post by Photographer’s Choice / Getty Images

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