24 de abril, 2026

How to Measure Maternity Bra Size: Complete Guide Before Birth

Quick Answer

To find your maternity bra size: measure your underbust and fullest bust, subtract to get cup size, use underbust as band size. Don't rely on pre-pregnancy sizing — your ribcage expands during pregnancy. If between sizes, size up in band and choose adjustable styles.

How Maternity Bra Sizing Works

Measure Your Underbust

Wrap tape around your torso, parallel to the floor, directly under your breast tissue. Keep it snug but not tight. This is your band size.

Measure Your Bust

Wrap tape around the fullest part of your breasts at nipple level. Keep the tape parallel to the floor and resting lightly — don't compress breast tissue.

Find Your Cup Size

Subtract underbust from bust. The difference determines cup size:

Difference (in)	Cup
1	A
2	B
3	C
4	D
5	DD
6	DDD/F

Example: 32" underbust + 38" bust = 6" difference → 32F. Note: sizing varies by brand.

Why Your Pre-Pregnancy Size Likely Won't Work

Ribcage expands to accommodate your growing baby
Hormones soften breast tissue and ligaments
Blood flow increases cause breast tissue to swell
Most women go up 1–3 band sizes during pregnancy

When to Measure

Maternity Bras: Measure in your second or third trimester when breasts have stabilized at their pregnancy size. Best time: end of day when breasts are full.

Nursing Bras: Measure 4–6 weeks before your due date or 1–2 weeks postpartum once milk supply stabilizes. Breasts change dramatically when milk comes in (2–5 days after delivery).

Postpartum: Re-measure if you experience significant changes in milk supply, weight, or breast size.

Re-measure when:

Band rides up or feels tight
Straps leave marks on the shoulders
Cups gap or overflow
Underwire digs into breast tissue

Maternity Bra vs. Nursing Bra

	Maternity Bra	Nursing Bra
Best for	Comfort during pregnancy	Breastfeeding access
Purpose	Accommodate growing breasts	Enable quick nursing
Key features	Soft fabric; stretch; wide straps	One-handed clips; drop cups
When to buy	Any time during pregnancy	4–6 weeks before due date
Closure	Pull-over or hook-and-eye	Hook-and-eye with clips

Which to buy? Early pregnancy: soft maternity bra or camisole. Late pregnancy or if breastfeeding: nursing-friendly style.

What to Look for in a Maternity Bra

Five features determine whether a bra actually works during pregnancy and postpartum.

Breathable Fabric

Cotton, bamboo, or moisture-wicking fabrics allow airflow. Pregnancy raises body temperature and increases skin sensitivity.

Adjustable Straps

Breast size changes throughout pregnancy and postpartum. Adjustable straps let you customize fit without buying new bras.

Adjustable Band

Multi-row hook-and-eye closures provide 2–3 inches of adjustability as your ribcage expands or contracts.

Stretch Content

Fabrics with 15–20% spandex/elastane accommodate daily fluctuations without feeling tight.

Wireless Design

Underwire increases the risk of blocked milk ducts and mastitis. Wireless styles provide sufficient support for most women.

Best Fit Tips

How to Measure:

Tape parallel to floor at all points
Snug but not compressing (one finger underneath)
Directly against skin, not over clothing
Stand naturally, don't suck in or puff out

Measure when breasts are at average or fullest size

Between Sizes?

• Choose adjustability over exact sizing

• Size up in band, not cup — a loose band can be tightened; an overflowing cup cannot

• Near delivery: prioritize nursing functionality. Earlier: prioritize comfort and growth room

Signs of a Good Fit:

Band sits horizontally without riding up
Cups fully encase tissue without gapping or overflow
Straps don't dig in or slip off
You can move and breathe without the bra shifting

Best Bra Options for Different Pregnancy Stages

Early Pregnancy (First to Mid-Second Trimester)

Breasts are growing but not yet at maximum size. Comfort is the priority. Nursing functionality isn't needed yet.

For light support during this stage: Built-in Bra High Stretch Camisole

85% Nylon, 15% Spandex. Comfortable, breathable, soft, and stretchy. Adjustable spaghetti straps and a built-in bra provide light support. The fabric moves with you during yoga, daily activities, or casual wear.

Late Pregnancy to Postpartum (Third Trimester Through Early Nursing)

Body is approaching maximum pregnancy size. A nursing-friendly style serves you through delivery and into breastfeeding. Prioritize adjustability and one-handed nursing access.

Primary recommendation: Nursing Bra Wavy Breastfeeding Bras

55% Nylon, 45% Spandex with jelly strips for excellent elasticity. Accommodates changing size throughout pregnancy and postpartum. One-handed breastfeeding clasp and adjustable shoulder straps enable quick feeding. Wireless, seamless design with silky touch eliminates irritation. Breathable semi-fixed pad stays in place during washing. V-neck, back U-shape, and high-stretch adjustable wide straps provide function and style.

Everyday Comfort and Layering

For days when less support feels better. Light-support tops work for lounging, errands, or layering under loose clothing.

For everyday layering: Women's Twist Front Crop Tank Top

Premium ribbed knit with excellent recovery. Built-in shelf bra and twist-front detail create shape while providing light support. Sleeveless racerback style for easy layering.

Learn More & Connect

At Ekouaer, our designs align with scientific standards and real-world comfort.

Health Standards: Our focus on comfort and temperature regulation follows maternal care principles recognized by clinical research on PMC.
Expert Feeding Tips: Our nursing-friendly features support breastfeeding best practices recommended by the CDC.
Community Choice: Explore real-world mom reviews and fabric tests on Reddit and YouTube.
Follow Us: Join our global community on Facebook, Instagram, Twitter & YouTube.

FAQ

Q: How do I know what size maternity bra to buy?

A: Measure underbust and fullest bust. Subtract to find cup size, use underbust as band. Prioritize adjustable straps and hook-and-eye closures.

Q: Should I size up during pregnancy?

A: Often yes. Many women need 1–3 more band sizes as the ribcage expands. If between sizes, size up in band and choose maximum adjustability.

Q: When should I buy a nursing bra?

A: 4–6 weeks before your due date, or 1–2 weeks postpartum once milk supply stabilizes. Avoid buying too early — breast size fluctuates significantly as milk comes in.

Q: What's the difference between a maternity bra and a nursing bra?

A: Maternity bras provide comfort during pregnancy. Nursing bras include one-handed clips or drop cups for breastfeeding access. Nursing-friendly maternity bras work for both.

Q: How often should I re-measure during pregnancy?

A: Re-measure if you experience size changes, discomfort, or fit issues. Many women measure at the start of the second trimester, third trimester, and near their due date.

Q: Can I wear a nursing bra during pregnancy if I'm not breastfeeding?

A: Yes. Many nursing bras are comfortable for pregnancy wear. Choose soft, wireless styles with stretch and adjustability.

Q: What if my breasts are different sizes during pregnancy?

A: Asymmetry is common. Measure both breasts and use the larger measurement for your cup size. Stretch fabrics and adjustable elements accommodate asymmetry.

Q: Do I need underwire in a maternity or nursing bra?

A: Most experts recommend avoiding underwire due to blocked milk duct and mastitis risk. Wireless styles provide sufficient support for most women.

About the Author

Written by the Ekouaer Editorial Team

About Ekouaer

Founded in 2014, Ekouaer is a leading maternity and nursing wear brand specializing in comfortable, functional clothing designed for pregnancy, labor, and postpartum recovery. Our Berlin Design Award-winning styles prioritize both safety and style, with all fabrics being OEKO-TEX certified to ensure the highest quality standards.

In partnership with airmid healthgroup, our designs are engineered for real-world comfort and have been recognized as an "Editor's Choice" by CNN Underscored, Forbes, and TODAY.com. Additionally, our specialized maternity essentials are proud recipients of the Mom’s Choice Awards. Explore the full range of nursing shirts and postpartum outfits in the Ekouaer catalog.