Facts About Breasts and Breast Health

Awareness of what is considered normal and what may need medical attention helps maintain breast health.

Your breasts can tell you a lot about your health. To keep your breasts healthy, being well-equipped with knowledge about breast health is key. So, here's what you should know about your breasts, as well as expert advice regarding breast health.

Your Breasts Don't Have to Be Symmetrical

"Something that a lot of people are uncomfortable about is asymmetry," Jennifer Wider, MD, women's health expert and author of "Got Teens? The Doctor Moms' Guide to Sexuality, Social Media and Other Adolescent Realities," told Health.

Breasts Can Be Different Sizes

For most people, both breasts are not the same size. So, small size differences between your breasts are completely natural. 

"The truth is that about 50% of women have uneven breasts. Usually, for reasons we don't really know, it's the left side that's a little bigger," explained Dr. Wider. "Our bodies, in general, are never perfectly symmetrical, so it's usually nothing to worry about." 

For example, gaining weight can cause your breasts to grow by increasing the size of the breasts' adipose, or fat, tissue cells. In contrast, if you lose weight by exercising, eating healthy, or having bariatric surgery, you may reduce weight-induced changes to the adipose tissue.

"Some women who start dieting and exercising to lose weight are surprised because one of the first places they lose it is in their breasts," added Dr. Wilder.

However, if you notice the size difference between your breasts changes from what you're used to for unknown reasons, contact a healthcare provider.

Breasts Can Be Different Shapes

Like breast size, breast shape can vary, as well. Some breasts sit high on the chest while others hang low. Also, a person's nipples may be more prominent or smooth and less noticeable than others.

"As more people are looking at social media or looking at pornography, they may get an idea of what breasts are 'supposed to' look like," noted Dr. Wider. "We need to throw that idea out the window because there is no right size or shape."

Of course, if a breast or a nipple suddenly begins to grow or unusually change shape, consult a healthcare provider, added Dr. Wider. 

"If it's always been that way, we're less worried about it," said Dr. Wider. "But if you've noticed something new, we want to take a look."

Breasts Change During Pregnancy

Breast size also changes with pregnancy. Although you might see your pre-pregnancy breast size return, it may take a while. 

"Sometimes women complain that their breasts look different after they've had a baby or that breastfeeding made their breasts deflated or hang lower," said Dr. Wider.

During the second trimester, milk ducts form, which is why a pregnant person's breasts may occasionally leak. Milk production then ramps up once the infant is born. During the first few days following delivery, your breasts produce thick, nutrient-rich colostrum. You'll start producing milk on the third or fourth day after delivery.

"Your breasts will fill up with milk whether you choose to breastfeed or not," said Dr. Wider. "If you don't breastfeed, your breasts will adapt and stop producing milk soon after. And if you do, they'll continue producing it for as long as there's demand."

It's possible, however, for pregnancy to change breasts in the long term. For example, you might develop permanent stretch marks on your breasts. 

Your breasts also might stay bigger or smaller than before after pregnancy. In some cases, you might not lose weight gained during pregnancy right away, causing your breasts to become larger and stay that way.

"I tell [pregnant people] that their breasts will probably bounce back to what they looked like before but that it may take a few months," explained Dr. Wider.

Breast Cancer

The size of your breasts does not increase your risk of breast cancer. 

"Women with larger breasts are not more at risk for breast cancer than women who have very small breasts," noted Dr. Wider. In fact, men, who tend to have very little breast tissue, can also get breast cancer.

Breast Cancer Risk Factors

"The risk factors for breast cancer include family history, alcohol consumption, and the age at which a woman gets her first period," Deanna Attai, MD, an assistant clinical professor at the David Geffen School of Medicine at the University of California in Los Angeles, told Health. "But they do not include her breast size." 

Several other genetic or environmental factors increase breast cancer risk, such as:

  • Inheriting certain genetic mutations
  • Being overweight or obese after menopause
  • Going through menopause later than 55
  • Being physically inactive
  • Having a personal history of breast cancer

A simple mail-away saliva test in the privacy of your own home can give insight into your family history and genetic risk of breast cancer.

"We used to need an elaborate and expensive blood test to find out these things," explained Dr. Wider.

If a genetic test reveals a mutation in one of your breast cancer (BRCA) genes, which increases your risk of breast and ovarian cancer, consult a healthcare provider. For example, you may opt for more frequent breast cancer screenings or preventative surgery.

Still, some experts warn that a test for a mutation in one of your BRCA genes doesn't tell the whole story. A negative test result doesn't mean you won't get breast cancer or can be lax about screenings and prevention strategies. In fact, many other genes can influence your breast cancer risk.

Also, those tests shouldn't take the place of regular breast cancer screenings or genetic counseling. Adopting a healthy diet and lifestyle is important to protect against breast and other cancers.

Breast Cancer Screenings

According to the American Cancer Society (ACS), you may begin annual mammograms at age 40. However, the ACS recommends having yearly mammograms at age 45. Then, at age 55, you may switch to every-other-year mammograms if you'd like.

However, if you have a family history of breast cancer or other risk factors, speak to a healthcare provider about possibly starting screenings earlier than normal. 

"As for young women who detect a breast lump or something unusual, mammograms usually aren't the best diagnostic option," said Dr. Attai. "These women will tell me their [healthcare providers] told them they're too young for breast cancer. They weren't given a mammogram, but they probably should have gotten an ultrasound or another form of imaging. We should never assume a woman is too young or discount her concerns."

Also, while breast self-exams are not part of the ACS's screening recommendations, healthcare providers may encourage people to do them. They may suggest you be familiar with how your breasts look and feel.

"I recommend doing [self-exams] monthly, not right before your period because breasts can get bumpy and lumpy at that time of the month," said Dr. Wider. "The best time to do it is seven to 10 days after you stop menstruating."

Dense Breasts May Increase Breast Cancer Risk

Mammograms can be difficult to read accurately if you have dense breasts. Dense breasts have higher amounts of glandular and fibrous tissue and less fatty, non-dense tissue than average. Research has found that dense breast tissue may be more likely to become cancerous than average.

For example, one study published in 2018 in Radiology studied more than 100,000 people. The researchers found that breast cancer rates were 6.7 per 1,000 exams for people with dense breasts and 5.5 per 1,000 for non-dense breasts. People with dense breasts also tended to have larger tumors, on average, than people with non-dense breasts.

Do Changes in Your Breasts Mean Cancer?

Lumps can appear in breasts at any time. However, lumps aren't always a cause for concern.

"One of the most common misconceptions is that every breast lump is cancer," said Dr. Attai. "Women will feel some sort of lump or thickening in their breast and immediately think the worst." In fact, lumps are common and are not likely to be cancerous, especially in young people. 

"All sorts of things can grow in the breasts, like cysts or benign tumors," said Dr. Attai.

You can also experience lumpiness in your breasts during different times, such as milk gland growth during pregnancy or hormonal changes as you approach menopause. They can also feel lumpier than usual before you get your period every month.

"Anyone who does feel something different should mention it to their [healthcare provider], just to be safe," said Dr. Attai. "But those people should also not freak out right away before they have more information."

Breast pain is another concern: "Many women who come in think there's something wrong because none of their friends have pain like this," said Dr. Attai. "But I think a lot more women do have it and just aren't talking about it."

For example, changing hormones may cause breast pain, which worsens before and during periods

"But some women will have pain not related to their cycle, and it can be very frustrating because often we don't find any particular cause," added Dr. Attai.

Talk with a healthcare provider if your breast pain or tenderness causes distress or disrupts your daily life.

"We'll do a workup, including an ultrasound, and get a sense of whether there are any medications or other factors that might be influencing the pain," said Dr. Attai. "But the good news is that the majority of breast pain is not related to cancer."

Nipple discharge is another breast-related concern. Still, the causes of nipple discharge are mostly harmless.

"If the discharge is yellow-greenish, light brown, or tan in color, it could be related to normal hormonal fluctuations," said Dr. Attai. To get a better sense of the color, blot the nipple with white tissue.

"Sometimes, discharge can be very dark, almost like motor oil, but that could still be a normal part of what we call a fibrocystic change," added Dr. Attai. "In most cases, the cause isn't serious, but it can be dangerous if not treated in a timely manner."

Still, consult a healthcare provider if any unusual discharge lasts longer than a few days or is clear or bloody. 

Irritated or itchy nipples can happen, too. Dry skin and sweat are common culprits, as is rubbing during exercise and exposure to chemical irritants, like laundry detergent. However, irritated or itchy nipples can also be a sign of breast disease or cancer.

"The majority of women who come see me with a rash or a red spot on their breasts have already Googled inflammatory breast cancer," said Dr. Attai. "We do a biopsy, and it's usually something else, but it's always better to be safe than sorry."

Mastitis, an infection of the breast tissue caused by a blocked milk duct, nipple piercing, or crack in the skin, can also cause inflammation.

"The infection usually goes away with antibiotics, but if your symptoms don't respond to treatment, see a breast cancer specialist to rule out cancer," said Dr. Attai.

Use a gentle moisturizer on your breasts, just like on the rest of your body, recommended Dr. Attai. 

"A lot of times when women complain about dry, cracked nipples, it can be related to dry skin," added Dr. Attai. "I have so many patients who think to put lotion on other parts of their body, but they never think about putting it on their breasts."

Also, minimize dry skin with the products you use in the shower. For example, you might opt to use a gentle, fragrance-free cleanser.

"I generally recommend using regular soap or body wash on your breasts and avoid going overboard with harsh chemicals that can cause irritation and dryness," said Dr. Attai. For example, expensive skin-care products explicitly marketed for "firming" or "enhancing" the breasts may cause irritation. 

"Besides being a little more sensitive around the nipples, the skin on your breasts is no different from the skin on the rest of your body," explained Dr. Attai.

There's No 'Best' Bra

The best bra for a person depends on their needs: "I get asked a lot, as a [healthcare provider], 'What's the best bra?'," said Dr. Attai.

"I wish there was one, but what I tell people is that the best bra for you is one that's reasonably comfortable and gives you some support," continued Dr. Attai. "That doesn't mean you don't still want to take it off at the end of the day, but you shouldn't spend the day tugging or readjusting or being in pain, either."

According to Dr. Attai, there's no evidence to support the popular theory that underwire bras cause breast cancer. Also, no evidence suggests that bras can prevent breast sagging later in life. 

However, bras can offer much support and alleviate shoulder or back pain. If your bra feels uncomfortable or pain persists, you may have been improperly fitted. 

"Taking the time to get fitted probably isn't a bad idea," said Dr. Attai. "Our breasts change as we age and go through life. So, chances are the bra size you wore in college may not still be the best bra size for you in your 30s or 40s," explained Dr. Attai.

Sports Bras Aren't Just for Comfort—They Can Improve Performance

As many active people realize, breast pain during and after exercise is a normal complaint.

The right sports bra can keep your breasts from moving during high-intensity exercise. Your breasts can move a vertical distance of up to eight inches during a hard workout.

Finding a supportive sports bra and avoiding common sports bra mistakes can help. Beyond comfort, running while wearing high-support bras makes running mechanics more efficient than when wearing low-support bras.

A Quick Review

Awareness of what is considered normal and what may need medical attention helps maintain breast health. 

Many changes in your breasts can be harmless. For example, if you're experiencing breast pain, it may just be related to hormone changes. Still, a visit to a healthcare provider may be necessary if pain or other symptoms keep you from going about daily activities. 

Was this page helpful?
Sources
Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Bhardwaj P, Brown KA. Obese adipose tissue as a driver of breast cancer growth and development: Update and emerging evidenceFront Oncol. 2021;11:638918. doi:10.3389/fonc.2021.638918

  2. Office on Women's Health. Making breastmilk.

  3. American Cancer Society. Breast cancer risk factors you cannot change.

  4. American Cancer Society. Lifestyle-related breast cancer risk factors.

  5. American Cancer Society. Understanding genetic testing for cancer risk.

  6. American Cancer Society. American Cancer Society recommendations for the early detection of breast cancer.

  7. National Cancer Institute. Dense breasts: Answers to commonly asked questions.

  8. Moshina N, Sebuødegård S, Lee CI, et al. Automated volumetric analysis of mammographic density in a screening setting: Worse outcomes for women with dense breastsRadiology. 2018;288(2):343-352. doi:10.1148/radiol.2018172972

  9. National Cancer Institute. Breast changes and conditions.

  10. American College of Obstetricians and Gynecologists. Benign breast conditions.

  11. Sajadi-Ernazarova KR, Sugumar K, Adigun R. Breast nipple discharge. In: StatPearls. StatPearls Publishing; 2022.

  12. American Cancer Society. Breast cancer symptoms: What you need to know.

  13. National Library of Medicine. Mastitis.

  14. American Academy of Dermatology. Dry skin: Tips for managing.

  15. Wood LE, White J, Milligan A, et al. Predictors of three-dimensional breast kinematics during bare-breasted runningMed Sci Sports Exerc. 2012;44(7):1351-1357. doi:10.1249/MSS.0b013e31824bd62c

  16. Milligan A, Mills C, Corbett J, et al. The influence of breast support on torso, pelvis and arm kinematics during a five kilometer treadmill runHum Mov Sci. 2015;42:246-260. doi:10.1016/j.humov.2015.05.008

Related Articles