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pregnancy bra size change

Feel like you’re not quite filling out that push-up bra, or spilling out of that demi-cup bra all of a sudden? You may not be imagining things.

Breasts can shrink or expand for a variety of reasons — and an augmentation surgery isn’t the only reason why your boobs might be looking bigger or smaller, either.

Here are some of the top factors that can cause a size change in your breasts:

Weight loss/gain

If you notice the number on the scale has changed, then your breast size likely has, too. It makes sense since your breasts are made up partly of fat tissue. This is more likely to occur if the weight shift has been significant (i.e., more than a few pounds). Naturally, if you’ve gained weight, you’ll increase in cup size, while your size will decrease if you’ve lost weight. (Pro tip: If your boobs are looking a little deflated after significant weight loss, a molded bra can help both lift and sculpt your breasts into a more desirable shape).


You may be surprised at how much your strength training regimen can impact your breasts. Working your back or chest muscles (located underneath the breasts) more often or more intensely can have an impact on your band size, for example. Additionally, depending on the type of workout your engaging in, you may see an overall decrease in body fat — and as that includes your boobs, your breast tissue could decrease as well.

Your period

Sensitivity and soreness aren’t the only breast-related PMS symptoms — your boobs can also change in size. Blame it on the hormones estrogen and progesterone, which fluctuate over the course of your cycle. Moreover, your body has a tendency to retain water during your period, which can make your boobs appear fuller. You will likely notice that the change is the most radical directly before you get your period, but rest assured your breast size will gradually return to normal either during your period or right after it ends.

Related: Why All Women Should Get A Professional Bra Fitting

does your bra size change when you lose weight


As your body begins preparing for breastfeeding, your bra size will probably begin to increase gradually over the course of pregnancy (starting as soon as week six or seven). That’s because all the ducts that contribute to milk production are swelling to get ready for lactation, and additionally, increases in hormones such as estrogen, progesterone, and lactogen lead glands in the breasts to grow. Every woman is different in this regard, of course, ranging from a slight increase to several cup sizes. You may notice an increase in cup size, band size, or both.


Looking pretty voluptuous as you begin nursing your new baby? It’s no surprise. As the milk comes in and the blood supply surges to your breasts, your boobs may feel fuller. However, once you start the weaning process and milk begins to dry up, your breasts will likely shrink back down. After this shift, your breasts may return to the size they were before pregnancy, or they may end up slightly larger or smaller than they were initially. Fun fact: Some women may notice that one breast gets larger than the other during breastfeeding, as it’s producing more milk. Fear not — a padded bra can help to even out the appearance of the breasts.


During menopause, there’s a noteworthy decline in estrogen as your body no longer recognizes a need for milk-producing glands, so one would assume that as a result, your breasts would decrease in density/fullness and overall size as the glandular tissue shrinks. However, that’s not always necessarily the case. In fact, in one 2004 study, 18.6 percent of the women who participated reported having to buy a larger bra size than they did pre-menopause, and only 1.7 percent reported needing a smaller size. This is likely due to the fact that weight gain and water retention are common during menopause.

Clearly, your bra size can change multiple times throughout your life as a result of various factors. That’s why it’s advisable to get a professional fitting at least once a year — you may not notice subtle shifts, and it’s crucial to be sure you’re wearing the correct size to look and feel your best.

Related: Can Your Bra Size Change After Menopause?

bra size changing

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Many specialty lingerie boutiques offer bra fittings. Their expert bra fitters will take the pain and frustration out of bra shopping and do all the work for you. Even better, their product knowledge can save you time and money. Plus, they know where all of the best bras are hiding.

If you’ve struggled with finding bras in the right size, it’s time to make a change. Visit our specialty store locator to find a store near you and schedule an appointment.

Happy bra shopping!

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Published by

Rebecca Strong

Rebecca is a Boston-based freelance writer who focuses on style, fitness, food, and travel. She has contributed to such publications as HuffPost, Elite Daily and U.S. News & World Report. When she's not writing, she can be found at home or in the studio working on the songs for her upcoming album. Her favorite bra is a black demi-cup style with all-over-lace — timeless and feminine.

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