Bra Sizing

Understanding the Size & Fit Struggle of Pumping & Nursing Bras

jolie ink pumping bra image from the front, woman with child

It's all too common for many of us to walk into a store and have trouble finding a regular bra that fits just right. The struggle is even more real for moms who are breastfeeding or pumping. Luckily, you don't have to be frustrated any longer when searching for the perfect fit. We're breaking down the sizing and fit struggle of pumping and nursing bras so you can feel good about your purchase. The Dairy Fairy Bras were created to solve these issues. You will love the look, feel, and function of these bras.

Nursing Mothers Have an Additional Challenge

An optimal breastfeeding and pumping bra should be comfortable, supportive, and easy to access. The bra needs to be easy to put on and take off. It also needs to be easy to wash, as they get covered in milk for obvious reasons. The last thing you want is a nursing or pumping bra that makes your life more difficult than necessary! Let's get into some specifics about what makes a good nursing/pumping bra.

Changes in Chest Size

Pregnant women experience fluctuation in breast size and bra sizing due to the growth and development of glandular tissue (milk ducts). A pregnant woman will see an increase in the number of blood vessels in her breasts as they get ready to feed the baby growing inside her. Maternity bras are out there, but there aren't many. It's important to find a bra with great support for maximum comfort.

After the placenta is delivered, progesterone drops. This combined with high prolactin levels causes copious milk production often referred to as your milk coming in. This happens around 48-72 hours postpartum. This increase in production is what causes engorgement, which is normal but if not properly managed can become a problem. With this comes a further fluctuation in breast size. It can be frustrating. Plenty of women buy new bras for their growing breasts during pregnancy and then find they have to buy EVEN MORE once the baby is born. Crazy right?

Nursing/Pumping Bras are Built Different

Nursing bras are made with added fabric along the cups because they are designed to let your breasts expand as they fill with breast milk in preparation for a baby's feed. They are more likely than not wireless bras. A nursing bra often has extra fabric in the cup, band, and straps. This extra fabric allows for your breasts to expand without added discomfort. This is especially important for women who are waiting for their colostrum to turn into milk. The added fabric will allow the bra to stretch when engorgement occurs. While nursing bras may not be required by all moms during pregnancy or after birth, many women find that they need one as soon as their milk comes in. They are convenient to have, but only once you find the right fit.

Our nursing and pumping bras make that process more convenient for you. Take a look at all of our styles and sizes here. 

Your Breasts Can Double or Triple in Size

Although you may have been wearing a B cup pre-pregnancy, your breasts, once expanded by a full feed and let down, could be as large as a C cup or even D cup. If you are unsure of your size and/or need to buy new bras, it can be difficult to know what size would fit best. The first step is to measure yourself in the following way:

  • Hold the tape measure straight and firm to give it a snug fit.
  • Use a soft measuring tape and take your band and bust measurements while wearing a non-padded bra or sports bra. Measure the fullest part of your bust.
  • Jot down your band measurement and add 3", for example, 33" + 3" = 36 band size. Round down for odd numbers.
  • Note your bust measurement and subtract your band measurement, for example 40" - 33" = 7.
  • The difference correlates to your cup size; 1 = A, 2 = B, 3 = C, and so forth.
  • If you don't see your size listed, don't despair, we often find that a lot of women are on the cusp and can find a great fit, even if they don't fall smack in the size chart. When in doubt, contact us and we will help with your bra fitting!

Find the correct bra size here using our sizing calculator!


Nursing Bras, Pumping Bras, and Regular Bras Are Not the Same

The fit of nursing bras is different because you need easy access to help you get through long hours of pumping or night feeds without causing any discomfort or soreness. Depending on your comfort level, you may sleep with your nursing/pumping bra on for extra support and to prevent leaks on the bedding.

You need to be able to get to your breasts quickly and unhook the bra easily using their detachable clip design. Many women have trouble with this step because they are wearing a poorly fitted bra that doesn’t have enough stretch or support in certain areas. If you are pumping, you need a bra that allows the pump parts to sit in the bra so you can work hand free. While many women will hold the pumps, it makes life easier when the bra works for us. The clip, access to the nipple for baby or the breast pump flanges, and extreme comfort are all important features for a breastfeeding bra.

Our cutting edge bras have been providing these features to make life easier for breastfeeding mothers for years. Be sure to check out our bralette collection, including the Rose!

The Problem Could be Poor Fit

When breastfeeding or pumping becomes challenging or painful, it's usually not the bra itself that is the problem but rather a poor fit. The best way to get through this awkward period as quickly and painlessly as possible is to select a nursing bra that fits correctly and feels comfortable.

Here are some things to consider when choosing a nursing bra:

  • Find one with adjustable straps—and choose ones that can be adjusted in multiple places for more versatility.
  • Make sure you can lift your arms above your head without feeling restricted by your bra's cup size.
  • Try on several styles until you find one that fits well and is comfortable enough to wear all day.

Our bras will leave you feeling comfortable and supported all day long. You won’t have to worry about disrobing to nurse or pump, the bra has all the features you need for success. The Ruby bralette is comfortable and sexy all at the same time. 


Don’t let a bad-fitting bra get in the way of your breastfeeding journey. With so many different styles available, you can easily find a good nursing bra that fits and supports your body. The key is finding quality materials that allow for flexibility as well as comfort. This is essential if you are experiencing changes in size during pregnancy and after birth, which can be common for nursing mothers. We hope this information has given you some insight into what makes up a proper fitting nursing bra as well as how to shop for one you love!

You can check out all of our nursing and hands-free pumping bra selections here. We offer flexible sizing for nursing and pumping bras, bras for wearable pumps, bras in different sizes, bras for large breasts, and more. They will be a game changer for your breastfeeding journey and are compatible with major breast pumps.

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