Your Healthy Breast Guide for Your 20s and 30s

by Sunny Sea Gold Health Writer

There are two major truths about women’s breasts: Every pair is different, and change is inevitable. From the first hormonal budding in early adolescence to the swelling (and shrinking back down) during pregnancy and breastfeeding, the breasts you have at 20 won’t be the same ones you’re walking around with at 40.

Here’s what every 20- or 30-something should know about her breasts.

Woman's belly with hot water bottle

Your Monthly Cycle Matters

Hormonal changes over the course of your menstrual cycle can lead to swelling, tenderness, and even lumpiness in your breasts. These are normal shifts called fibrocystic breast changes. You may also notice round, tender lumps that get bigger and more tender in the week before you start your period and then shrink back down soon after. These are most likely fluid-filled cysts, says the American Cancer Society—and aren’t dangerous.

Fibrocystic change in breast under microscope

Some Breast Lumps Are Normal

Some women in their 20s and 30s have rubbery, firm, or hard tissue in their breasts called fibrosis. Like cysts, this lumpiness is generally nothing to worry about, according to the American Cancer Society. But if only one breast is lumpy and not the other, have a doctor check it out, says William Owens, M.D., director of the Aurora BayCare Medical Center Comprehensive Breast Care Center in Green Bay, WI.

A Good Sports Bra Is a Good Investment

No matter how perky your pair may be, it’s still important to invest in a supportive sports bra. Because there are no muscles in our breasts to hold them up, unsupported movement can overstretch the thin ligaments that connect them to your chest wall, leading to sagging and pain. And breasts move around quite a bit, even when you’re just walking. One study by researchers at the University of Portsmouth in the United Kingdom found that your breasts jiggle in a figure-eight motion as you walk or jog—they can move up to six inches out of their original position while running.

polka dot bra on clothesline

Speaking of Bras...Wash Yours!

Walking around in a dirty, sweaty bra can lead to skin issues, says Joshua Zeichner, M.D., director of cosmetic and clinical research in dermatology at Mount Sinai Hospital in New York, NY. “Sitting in wet clothing that sticks against the skin may lead to folliculitis, a mild infection of the hair follicles that looks like pus pimples,” he explains. “Especially underneath the breasts, the wet environment can also promote overgrowth of yeast and bacteria, leading to a condition called intertrigo—where the skin becomes red and itchy.” Sometimes these rashes require prescription treatment.

young woman with cancer wearing headscarf

Don’t Assume You’re "Too Young" for Breast Cancer

Only 3% to 4% of all new cases of breast cancer diagnosed in 2017 were in women under age 40, according to the American Cancer Society. That said, breast cancer in young women tends to be more aggressive than it is in older women. “Because breast cancer in young women is uncommon, sometimes even their primary-care physicians aren't thinking that it's a real risk for them,” says Mariana Chavez MacGregor, M.D., an assistant professor of breast medical oncology at the MD Anderson Cancer Center in Houston, TX. That means it’s even more important for women in their 20s and 30 to know the signs and symptoms to look out for.

Young woman having a mammogram

You May Need a Mammogram Earlier Than You Think

Most women don’t need a mammogram until age 40, but if your personal risk of breast cancer is higher than average, you may need to be screened earlier. “Patients with a significant family history of breast cancer, breast-cancer gene mutations or other high-risk genetic syndromes, or a history of chest radiation may be recommended to start screening at age 30 or earlier,” explains Rebecca Teng, M.D., an ob-gyn with Women’s Health Texas in Round Rock, TX. “Younger women in their 20s and 30s, depending on their risk factors and clinical situation, may also require ultrasound or MRI along with mammograms.”

young woman smiling looking at pregnancy test

Early Signs of Pregnancy Can Show Up in Your Breasts

Some of the first things you may notice in the early days of pregnancy are pain, tenderness, and swelling in your breasts. “This is due to increased levels of estrogen and progesterone during pregnancy,” explains Huma Farid, M.D., an ob-gyn at Beth Israel Deaconess Medical Center in Boston, MA. Later in pregnancy, hormone changes can also darken the color of your nipples. “Some women also notice tiny ‘bumps’ on the nipples—those are glands that secrete lubrication in preparation for breastfeeding. It only happens during pregnancy,” says Dr. Farid.

woman doing reformer pilates

What You Do Today Matters Tomorrow

Exercising regularly and eating a nutritious diet are both linked to a lower risk of breast cancer. There’s no exact prescription for exercise, but the American Cancer Society suggests you get at least 150 minutes of moderate exercise (walking, yoga, yard work) or 75 minutes of vigorous exercise (jogging, swimming, soccer) per week. Watching how much you drink is important to breast health, too. The Centers for Disease Control and Prevention recommends that women have no more than one drink per day. Studies have found that sipping between seven and 14 drinks a week is associated with a 30% to 50% increase in risk of breast cancer, according to 2013 research published in the journal Current Breast Cancer Reports.

woman looking in bathroom mirror unfastening towel

Knowing Your Normal Is Key

Some doctors encourage their patients to give themselves breast self-exams every month. “It is very important for women to get to know their breasts,” says oncologist Jonathan Stegall, M.D., medical director at The Center for Advanced Medicine, an integrative cancer treatment center in Alpharetta, GA. The bottom line is that you’ll want to know what’s normal for the look and feel of your breasts so that you’ll notice when there’s a change in texture or appearance. The Komen Breast Cancer Foundation has a quick and simple way to do a self-exam: Simply stand naked in front of a mirror and ask yourself a few simple questions about what you see and feel, from sudden nipple discharge to new knots or warm spots.

Sunny Sea Gold
Meet Our Writer
Sunny Sea Gold

Sunny is a health journalist with deep expertise in women's and children’s health who has written for some of the largest and most well-known print and digital publications in the United States. She’s also the author of the book Food: The Good Girl’s Drug, and writes essays and reported pieces on body image, eating disorders, parenthood, and mental health. She lives in Portland, OR, with her husband and two daughters.