Maternity Bra Size Guide — How to Find Your Size During Pregnancy

One of the most common questions expectant mothers ask is: When should I buy a maternity bra?

The answer is simple: when your current bras stop feeling comfortable.

Many women assume they should wait until their bump becomes visible, but breast changes often begin during the first trimester. Hormonal fluctuations can cause swelling, tenderness, and increased breast volume within the first few weeks of pregnancy.

Signs it may be time to switch to a maternity bra include:

• Cups feeling tight or restrictive
• Underwires digging into breast tissue
• Increased breast sensitivity
• Straps leaving deep marks on shoulders
• Difficulty fastening your usual bra comfortably

The best maternity bras are designed to accommodate growth while providing gentle support. Choosing a maternity bra early can help prevent discomfort as your body changes throughout pregnancy.

Every pregnancy is different, but most women experience several stages of breast growth.

Because your body is constantly changing during pregnancy, it's important to check your measurements regularly.

Step 1: Measure Your Band Size

Using a soft measuring tape:

• Measure directly underneath your bust
• Keep the tape level around your body
• Ensure it feels firm but comfortable

This measurement helps determine your band size.

Step 2: Measure Your Bust

Measure around the fullest part of your breasts while wearing a non-padded bra.

Make sure:

• The tape remains level
• You are standing naturally
• The tape is not pulled too tightly

Step 3: Calculate Your Size

Compare your measurements using our Bra Size Chart:

Bra Size Chart

Because maternity sizing can vary between individuals, it's worth checking your size every few months throughout pregnancy.

If you're unsure about your measurements, our online Fit Quiz can help identify the most suitable styles for your needs:

Fitting Room

For personalised assistance, professional bra fittings are also available in-store. Find your nearest location using our Store Locator:

Store Locator

A professional fitting can be particularly helpful if you're experiencing significant breast growth or are shopping for supportive maternity bras for the first time.

Women with fuller busts often have additional considerations when choosing maternity bras.

If you wear a D, DD/E, F, or larger cup size, support becomes even more important as your breasts grow during pregnancy.

When shopping for maternity bras for large breasts, look for:

• Wider shoulder straps
• Strong underband support
• Full-coverage cups
• Multiple hook-and-eye adjustments
• Flexible sizing options

Larger busts place additional pressure on the shoulders, neck, and back, making proper support essential for comfort.

Women searching for plus size maternity bras should prioritise fit and support rather than sizing up unnecessarily. A properly fitted maternity bra should provide support without creating pressure points or restricting breast tissue.

Many maternity bra styles are designed specifically to accommodate larger cup sizes while allowing room for ongoing growth throughout pregnancy and breastfeeding.

The best maternity bra depends on your stage of pregnancy, lifestyle, and personal preferences.

Wire-Free Maternity Bras

Wire-free maternity bras are among the most popular options during pregnancy.

Benefits include:

• Flexible comfort
• Reduced pressure on sensitive breast tissue
• Greater adaptability to size changes
• Comfortable all-day wear

Many women choose wire-free styles during periods of rapid breast growth.

Flexiwire Maternity Bras

Modern flexiwire designs offer structured support while maintaining flexibility.

Benefits include:

• Additional lift
• Enhanced shaping
• Support for larger cup sizes
• Improved separation

For women with fuller busts, flexiwire styles can provide a balance between support and comfort.

Nursing and Drop-Cup Bras

If you're planning to breastfeed, nursing bras are worth considering during late pregnancy.

Features often include:

• Drop-down cups
• Easy feeding access
• Flexible sizing
• Soft internal support

Many maternity bras are designed to transition seamlessly into nursing bras, offering long-term value after your baby arrives.

Choosing the Best Maternity Bra

The best maternity bras are those that adapt to your changing body while providing reliable support.

Look for features such as:

• Stretch fabrics
• Adjustable straps
• Multiple hook positions
• Breathable materials
• Full cup coverage

If you're unsure where to start, browse our full maternity collection at /collections/maternity to find styles suited to every stage of pregnancy and breastfeeding.

What size maternity bra should I buy?

Choose a maternity bra based on your current measurements rather than guessing future growth. Look for adjustable styles that provide flexibility as your body changes throughout pregnancy.

Do maternity bras run bigger than regular bras?

Not necessarily. Maternity bras are designed differently to accommodate growth and comfort, but you should still begin with your current bra size and use a sizing guide to find the best fit.

Can I use my regular bra during pregnancy?

You can continue wearing regular bras if they remain comfortable and supportive. However, many women find maternity bras become necessary as breast size, sensitivity, and rib cage measurements change.

When should I switch to a nursing bra?

Many women switch during the third trimester, particularly if they choose a maternity bra designed for both pregnancy and breastfeeding. Nursing bras become especially useful once feeding begins after birth.

Pregnancy is a time of constant change, and your bra should adapt with you. Whether you're searching for the best maternity bra, researching supportive maternity bras, or looking for maternity bras NZ that provide comfort throughout pregnancy and breastfeeding, the right fit can make a significant difference.

By measuring regularly, choosing flexible sizing options, and prioritising support, you'll be better prepared for every stage of pregnancy and beyond. Investing in a well-fitted maternity bra today can help you stay comfortable, supported, and confident as your body continues to change.