From darkened nipples to sagging, here's how your breasts may evolve—decade by decade.

Sarah Klein
November 06, 2017

When it comes to breast cancer screening, there's one piece of advice that's pretty much universal: know your breasts. The idea is that the more familiar you are with your girls, the more likely you are to notice any potential signs of cancer, such as lumps, dimpled skin, or swelling on one side. But as you keep tabs on your boobs, it may be helpful to know there are a host of other breast developments that are completely normal. Here's a look at the many ways your boobs can change throughout different phases of your life.

RELATED: 9 Breast Cancer Symptoms That Aren’t Lumps

Puberty

Everyone’s born with some breast tissue and nipples; but it isn’t until puberty that our boobs as we know and love them start to show up. When a young woman's body prepares to ovulate and menstruate, “estrogen and progesterone kick it into gear,” says Christine Greves, MD, an ob-gyn at Orlando Health Hospital. “Our mature mammary glands start to develop, and by the time of our adult life, we have what you and I know as breast tissue.” This process even has a fancy medical name: thelarche. And it’s usually complete by the time you turn 20, Dr. Greves adds.

In addition to breasts, you might have also gained some stretch marks during puberty. When breasts grow quickly, “the skin cannot keep up," says Dr. Greves. “There’s nothing to really do about stretch marks if you’re destined to get them.”

RELATED: 20 Things You Need to Know About Your Nipples

Your 20s

By now your boobs are fully formed, and with any luck, your menstrual cycle has settled into a regular routine. It’s common to notice breast changes before or during your period, thanks to fluctuating hormone levels. “Around our period, just like we feel bloated, fluid increase applies to the breast tissue too,” Dr. Greves says. You might notice you're more voluptuous than usual–or possibly in a bit of discomfort. “The swelling can make breasts more tender during that time,” she says.

In some people, that extra fluid can also cause lumpiness, according to the National Cancer Institute (NCI). Talk to your doctor if these lumps concern you; he or she may want to do an exam and see you again at a different point in your cycle.

At this time in your life, your breasts are at their firmest and perkiest. They're also at their densest—which means they contain more fibrous tissue (think glands and ducts) and less fatty tissue. (For more, check out this explainer on what it means to have dense breasts.)

RELATED: The 5 Ways Your Boobs Change Throughout the Month

Your 30s and 40s

Many women have children during these decades, and pregnancy and breastfeeding can usher in more breast changes. When you're pregnant, more milk-producing lobules develop and the milk ducts start working, Dr. Greves says. These gland changes can sometimes feel like lumps. (You should still mention any lumps you detect to your doctor.)

You may also notice that your areolas get darker during pregnancy. “We don’t really know why, but some say it’s because babies’ vision is only good at telling the difference between light and dark,” Dr. Greves says. If the area right around the nipple is easier to distinguish from the rest of your breast, the theory goes, your baby might have an easier time breastfeeding.

Both pregnancy and breastfeeding can add some heft to your chest. “Just like puberty, pregnancy or breastfeeding causes breasts to enlarge very quickly over a short period of time,” Dr. Greves says, which can result in more stretch marks.

Breastfeeding can also cause some lumpiness to develop. If this lumpiness is accompanied by soreness, warmth, or a reddish hue in your skin, you could have an infected or blocked milk duct, called mastitis, which is treatable with antibiotics.

Whether or not you get pregnant in your 30s or 40s, “gravity takes effect” during these decades, Dr. Greves says. Some amount of breast sagging is pretty much unavoidable. The ligaments in your breasts simply stretch out over time.

RELATED: 6 Weird Ways Pregnancy Changes Your Breasts

Your 50s

“I see a lot of patients with complaints like, ‘My breasts were so nice and supple before, and now they hang down!’” says Dr. Greves. Some of that sagging may be the result of prior pregnancies and breastfeeding; but some is caused by the hormonal shifts of menopause.

“As we get older, the levels of estrogen and progesterone decrease,” explains Dr. Greves. Estrogen and progesterone fuel the growth of glands, ducts, and other non-fatty tissue in the breasts; so as those hormones decline, the breasts end up with more fatty tissue. “Breast tissue may not be as round and may sag a little bit more,” she says.

After menopause, the skin on your breasts can change as well. It may become drier and thinner, says Dr. Greves, which may also contribute to a droopier appearance.

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When in doubt, speak up

While many breast changes are normal and nothing to worry about, if you discover anything that concerns you, mention it your primary care physician or ob-gyn, Dr. Greves urges: “Bring it up, and don’t be shy.” It's always best to err on the side of caution.