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Breast development is often the first sign of puberty for girls in the pre-teen and teen years. For parents, breast development can raise questions and concerns, especially when it occurs earlier or later than expected. From the first signs of puberty to changes during adolescence, understanding the stages of breast development and when breast development ends can help parents navigate this important phase in their daughter’s life.
In this breast growth and development guide, we’ll explore what’s considered healthy development, potential causes of early or delayed breast development and when to seek medical advice. At Texas Children’s, our specialists are here to provide expert care and answers for every step of your child’s journey.
What is breast development?
Breast development, or the growth of a girl’s breasts, is often the first sign of puberty for females. It can be a time of excitement as well as anxiety, as girls get used to their changing body.
Patients can be seen by Texas Children’s experts in Pediatric and Adolescent Gynecology.
What happens during breast development?
The first sign of breast development is slight swelling under the nipple, a stage of development called breast buds. As breasts first start to grow, they can be very tender and sore. They may also itch as the skin is stretched. Buying a first bra can help protect new breast growth and minimize pain. If the breasts grow rapidly, stretch marks may occur in the skin. These will fade over time.
Breasts will continue to grow as the girl’s body fat increases during puberty. They become rounder and fuller. The areola (the area around the nipple) may get darker and larger and the nipple may become erect, or stick out. It’s common for one breast to develop faster than the other. Over time this difference in breast size should even out, however many adult women find their breasts differ slightly in size. This slight variation in breast size is completely normal.
When does breast development start and stop?
- In general, breast development begins between the ages of 8 and 13.
- A girl’s breasts are typically fully developed by age 17 or 18. However, in some cases, breasts can continue to grow into a woman's early 20s.
At what age are breasts fully developed?
Breast development is a gradual process that typically begins during puberty, around ages 8 to 13, and continues through adolescence. For most girls, breasts are fully developed by the late teens or early 20s, though this can vary based on genetics, hormonal factors and overall health.
While the physical size and shape may change throughout life due to factors like pregnancy, weight fluctuations or aging, the primary stages of breast development are usually completed during young adulthood.
If you have concerns about delayed or early development, consulting a health care specialist can provide valuable insights.
Preteens, teens and developing breasts
Many preteens and teens worry about when and how their bodies will develop. When a friend or even a younger sibling develops first, girls may worry something is wrong with them. On the other hand, girls who are among the first to develop often feel self-conscious. Normal breast development varies and progresses at different rates for each person.
Reassure your preteen or teen that it’s perfectly normal for breast development to start anytime between ages 7 and 13. A girl’s first menstrual period will typically happen about 2 to 2.5 years after breast development begins.
Stages of breast development
| Female breast development stage | What to expect |
|---|---|
| Stage 1 | No breast tissue can be felt |
| Stage 2 | Breast buds appear; usually the first sign of puberty |
| Stage 3 | Breasts become larger with tissue that can be felt outside the area around the nipple (areola); no areolar development |
| Stage 4 | Areola and nipple become elevated above the breast contour, forming a “double scoop” appearance |
| Stage 5 | Fully developed adult breast. The area around the nipple (called the areolar mound) recedes, with breasts forming a rounded shape |
Breast changes during pregnancy
During pregnancy, several changes happen to a woman’s breasts as well:
- Around 6–8 weeks of pregnancy, breasts become bigger and continue to grow throughout pregnancy.
- Breasts often become more tender and sensitive.
- Nipples and areolas may darken due to hormones.
- Due to increased blood supply, veins may become darker.
- Around the end of the first trimester, breasts may start leaking colostrum (a yellowish, thick substance).
- Nipples and areolas typically become larger, and nipples may protrude more. Areolas may also develop bumps, which are oil-producing glands.
Breast development: Concerns about normalcy
While there’s a wide range for what’s considered normal breast development, some changes aren’t normal. Look for unusual symptoms such as:
- Breasts developing earlier than age 8
- No breast buds or breast development by age 13
- Breast abscess
- Breasts that are significantly different sizes
- Inverted nipples (pointing inward)
Learn more about breast abnormalities.
When should I take my child to see a doctor if we have breast development concerns?
If you notice any of the above symptoms or have other concerns about breast development, talk with your child’s pediatrician or a specialist, such as the experts in Texas Children’s Pediatric and Adolescent Gynecology Program.
Frequently asked questions about breast development
Breast development is caused by hormones released by the ovaries at puberty. These hormones cause fat to accumulate, causing breasts to enlarge. The duct system in the breast also begins growing.
Usually, breast changes begin around the same time as public and armpit hair appear.
Changes in hormones during a girl’s monthly period can cause changes in the breasts, too.
These monthly changes may include swelling, pain, tenderness and, in some cases, changes in breast texture, with the breasts feeling lumpier.
Breast size varies widely and is primarily determined by heredity. Because breasts contain fat cells, a girl’s breasts size will increase with weight gain.
It’s common for one breast to develop faster than the other. Over time this difference in breast size should even out, however many adult women find their breasts differ slightly in size.
However, if breasts are significantly different sizes, consult a health care provider.
Yes, having some pain or tenderness is normal as breasts develop. A bra may help to minimize discomfort.
In most cases of delayed breast development, puberty-related changes start later than usual but progress normally. People may use the term “late bloomer.”
Lack of body fat is another common reason for delayed breast development, often affecting girls who are very active in sports, have an eating disorder or don’t eat enough to maintain good health.
Less frequently, other conditions or treatments can delay normal growth and development. If your child is over 13 and hasn’t developed breast buds, consult a health care provider.
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