Breasts change with age. Here's why, according to experts.

There is a misconception that breasts reach their forever state at the end of puberty. In reality, that’s only the beginning of their ever-changing appearance and feel. As Dr. Cara Natterson and Vanessa Kroll Bennett, co-hosts of The Puberty Podcast, put it in a recent Instagram post, breasts stop growing “kind of never” — or rather, they change over a lifetime.

We spoke to experts to better understand how breasts can change over time and why they fluctuate.

How do breasts change with age?

First and foremost, it’s important to note that breast changes are “a natural part of the aging process,” Dr. Mindy Goldman, ob-gyn and chief clinical officer at Midi Health, tells Yahoo Life. However, these changes are more common in some people than in others, genetics being the main influence, she notes. In general, though, the most significant transformations tend to happen as a result of hormone fluctuations.

“Hormones, particularly estrogen, play a crucial role in breast development and maintenance,” Goldman explains. Breasts have three main components: skin, fibroglandular tissue, which is composed of milk-producing lobes and ducts, and filler-esque fat that surrounds said tissue, Dr. Tommaso Addona, plastic surgeon and president of New York Plastic Surgical Group, tells Yahoo Life. Estrogen stimulates the development of the fibroglandular tissue, Goldman says, and therefore, any type of estrogen fluctuations inherently increase the likelihood for breast changes to happen.

With that being said, “hormonal factors are highly individual,” says Goldman, and can affect people differently. Generally speaking, these events can trigger breast changes:

Periods

Throughout a menstrual cycle, the ovaries produce estrogen to prepare for ovulation or potential pregnancy, according to Mount Sinai. This spike triggers milk duct growth within the fibroglandular tissue and results in temporary swelling and potential lumpiness or tenderness of the breasts, according to John Hopkins Medicine. If pregnancy doesn’t occur, breasts return to their “normal” size and state.

Pregnancy and breastfeeding

In that same vein, breasts are destined to change during pregnancy, as estrogen progressively rises in preparation for breastfeeding, Goldman explains. Breasts typically increase in size — going up a cup size or two — at around six to eight weeks, according to the American Pregnancy Association, and then can “deflate” when a person stops breastfeeding and milk-producing cells die off. That said, some women find their breasts stay larger even after they’ve stopped breastfeeding.

Menopause

Menopause — the transition marked by 12 months without a menstrual cycle, which happens on average by age 51, per Mayo Clinic — usually prompts significant breast changes. That’s because menopause is characterized by a drop in estrogen and therefore a loss of fibroglandular tissue, which is replaced by an increase of filler fat.

This new breast composition can result in decreased breast density, which can physically manifest as breast sagginess. “Without estrogen, the glandular tissue shrinks, making the breasts smaller and less full,” Dr. Steven Quay, a breast health researcher, tells Yahoo Life. “The connective tissue that supports the breasts becomes less elastic, so the breasts sag.”

And while that may sound like a negative development, Dr. Jacqueline Holt, medical director of women’s imaging for Delaware Imaging Network, tells Yahoo Life that less dense breasts can be a good thing, as they make breast cancer easier to detect during a routine mammogram. She adds that changes in breast density may not always reflect changes in breast size. “It doesn’t mean your breasts will get bigger or heavier. It is a shift in your breasts with age that is genetic,” she explains.

Goldman notes that menopause-related changes in breast density may also result in new breast textures and nipple changes. “Breasts may become softer or feel different,” she explains. “The nipples may undergo changes in size, shape or position.”

Weight fluctuation

Weight gain or loss can affect the size of the breasts, as they are composed partly of fatty tissue, says Goldman. “Although the exact impact of diet on breast tissue is not known, maintaining a healthy weight through regular exercise and a balanced diet may have positive effects on breast composition and risks for cancer,” she says.

Breast cancer

While many breast changes are normal, some — like lumps and unexplained skin changes — can be major health red flags. For example, breast tissue that has an orange peel appearance can be a sign of inflammatory breast cancer. “The risk of developing breast cancer increases with age,” says Goldman. “Regular breast screenings, such as mammograms, are an important part of health screening for women so that any potential abnormalities can be diagnosed early.”

Holt says that “knowing your breasts — their normal appearance, feel and shape — is the best way to personally look after your health, but it does not replace the accuracy of a mammogram.” She adds: “If you ever feel a lump in your breast, especially when it is unfamiliar to you, that is to be taken seriously. See your physician, who will order tests to evaluate the situation.”