Pregnancy causes many changes in a woman’s body, including changes to the breasts. As the breasts grow larger during pregnancy, most women find they need to go up 1-3 bra sizes to maintain comfort and support. Choosing the right bra size during pregnancy is important for reducing back and neck pain, providing adequate breast support, and accommodating changing breast size.
How much do breasts grow during pregnancy?
On average, women’s breasts grow 1-2 cup sizes during pregnancy. However, it varies significantly by individual. Here are some general guidelines on breast growth during pregnancy:
| Trimester | Average Growth |
|---|---|
| First Trimester | Breasts start to feel tender and full. Some slight growth of 1/2 to 1 cup size. |
| Second Trimester | More noticeable breast growth of 1-2 cup sizes. |
| Third Trimester | Breasts reach final size with a 1/2 to 1 cup size increase. Growth slows down. |
Breast growth starts as early as 1-2 weeks after conception as the body ramps up estrogen production. The most rapid growth typically occurs in the first half of pregnancy. By full term, it is common for breasts to grow 1-3 cup sizes from pre-pregnancy size. However, each woman’s breast growth during pregnancy is unique. Genetics, breast tissue density, age, and number of pregnancies all affect breast growth rates.
How often should bra size be measured during pregnancy?
Experts recommend getting your bra size measured every 4-6 weeks during pregnancy as your breasts grow and change shape. Here are some key times to get re-measured:
- When your current bra feels tight or uncomfortable
- If breasts are spilling out of the cup
- When going up a cup size
- Every month through the second trimester as growth is rapid
- Anytime breast shape seems to change
Keep in mind that breast size can fluctuate daily during pregnancy, so getting sized more than once a month is often needed for the most accurate fit. It’s ideal to get sized at a specialty lingerie store for expert help. If that’s not possible, use an online bra size calculator or try the “at home” measuring technique.
What bra size measuring system is best?
Two main sizing systems are used for bras today:
Standard Sizing
This is the traditional bra sizing system using band size and cup letter. For example, 34C. It is the most commonly used sizing method. However, standard sizing does not account for differences in breast shape. Women with the same measurements can have very different fit needs. Standard sizing also does not indicate larger cup sizes clearly. Once above DD, sizing starts doubling letters, which can be confusing.
Continuous Sizing
This newer sizing system uses inches for both band size and cup size, providing more precision. For example, 34D would be 34-7 in continuous sizing. The inches represent the difference between overbust and underbust measurements. This system accounts better for shape and larger cups. However, it is not as widely adopted in the US yet.
For most women, standard sizing is adequate for getting a comfortable bra during pregnancy that accommodates growth. However, women with larger cup sizes pre-pregnancy may find continuous sizing gives them more options. Try both systems to determine which provides the best fit for you through all stages of pregnancy.
What are sister sizes?
Sister sizes refer to different band-cup size combos that have the same cup volume. As the band size decreases, the cup size increases. This principle allows you some flexibility in bra sizing. Here are two examples of sister sizes:
- 34C and 36B hold the same cup volume
- 38DD and 40D hold the same cup volume
Sister sizes are useful during pregnancy because you may need to go up or down a band size while keeping the same cup volume. Going up a band size on your current bra and down a cup size is an easy way to get a close fit before getting re-measured.
What bra features are most important during pregnancy?
Look for these features when shopping for pregnancy and nursing bras:
Soft, Wide Side Panels
Flexible side panels and edging allow the cup to comfortably expand as your breasts grow larger. This prevents pinching and discomfort.
Wide, Adjustable Straps
Adjustable straps accommodate changes in breast size and shape during pregnancy. Wider straps stay comfortable as they take on more breast weight.
Front Adjustable Band
Being able to adjust the band size as you grow is essential for getting a perfect fit during all trimesters. Extender hooks allow you to make the band looser as needed.
Underwire/Wireless
Underwire bras provide more lift and shape, while wireless bras prioritize comfort. What you choose depends on personal preference and breast sensitivity during pregnancy. If experiencing tenderness, go wireless until that subsides.
Full Cup Coverage
As breasts grow larger, a full coverage cup minimizes spillage for the most support. This also allows room for any breast size fluctuations day-to-day.
Breathable Fabrics
Look for natural, breathable fabrics like cotton to keep breasts cool and prevent sweat buildup as breasts heat up during pregnancy. Breathable cups also aid milk production when nursing.
How should a bra fit during pregnancy?
Here are signs that a bra fits properly during pregnancy:
- Band fits snugly without pinching or digging in
- Breasts are fully encased in the cup, no spillage
- Underwire lays flat against chest wall (if underwire bra)
- Gore (center part) tacks closely to breastbone
- Straps don’t dig into shoulders
- Bra feels comfortable and supportive
The band should fit quite snugly to provide enough support as breasts grow heavy. A too loose band results in inadequate support. Cups should fully encase breasts without spillage or gapping. If adjusting to the outer hooks or sizing up the band still results in poor fit, it’s time to go up a cup size.
How to measure for bra size at home
You can get a pretty accurate bra size measurement at home with just a soft tape measure. Here are the steps:
- Wear a non-padded bra and stand in front of a mirror. Lift breasts up into the cups.
- Measure underbust tightly around the ribcage, just below breasts. Exhale first. Record to nearest 1/2 inch.
- Measure around fullest part of bustline. Keep tape parallel to floor. Record to nearest 1/2 inch.
- Subtract underbust measurement from overbust measurement. The difference indicates cup size.
- Compare band size to commercial bra sizes. Sister size down if between band sizes.
1 inch difference = A cup
2 inches = B cup
3 inches = C cup
4 inches = D cup
5 inches = DD/E cup
Re-measure every 4-6 weeks during pregnancy as breast size changes. Bend forward when measuring overbust to get the most accurate measurement. Have someone assist you for best results.
How do cup and band size correlate?
Cup size is not a static measure but depends on the band size. This chart shows how cup size scales to band size using standard sizing:
| Band Size | Cup Size |
|---|---|
| 30 | A |
| 32 | B |
| 34 | C |
| 36 | D |
| 38 | DD/E |
As the band size increases, so does the cup letter for the same breast volume. This is why sister sizing down band size and up cup size works. Pay attention to this as your ribcage may expand during pregnancy requiring a larger band for the same cup volume.
What bra styles work best during pregnancy and nursing?
Stretchy Bralettes
Bralettes provide light support and flexibility for fluctuating breast size during pregnancy and nursing. Seamless style and wide bands smooth the silhouette under clothes.
Sleep Bras
Supportive camisole-style sleep bras keep swelling and leaking contained overnight without sacrificing comfort. Breathable cotton and wire-free design make them ideal for rest.
Full Figure Bras
Designed specifically for D-G cup sizes, full figure bras come in underwire and wireless options with wide straps, cushioned cups, and reinforced bands needed for heavy breasts.
Sports Bras
Encapsulation style sports bras limit bouncing during activity. Underwire free and breathable with thick straps and bands, they also work well for sleep support.
Nursing Bras
Flap down cups allow easy breastfeeding access. Look for soft, flexible cups without underwire that comfortably accommodate frequent size changes.
How much do bra sizes change after delivery?
There is significant breast size fluctuation after delivering as milk comes in and stabilizes over the first weeks. It’s normal to go down 2 or more cup sizes from peak pregnancy breast size once milk supply regulates around 4-6 weeks postpartum.
Ribcage size also decreases by several inches as uterus shrinks back down over the initial 6 weeks postpartum. Factor in these expected body changes when purchasing nursing bras for after delivery.
Conclusion
Frequent bra size re-measuring and sister sizing are key for dialing in the optimal fit through all trimesters of pregnancy. Focus on support, comfort, and adjustability when choosing bras. Undergoing body changes can be challenging, but finding properly fitted bras helps mamas feel their best during pregnancy and beyond.