Why Are My Breasts Growing In My Early 20s?

Breast growth is most commonly associated with puberty where an increase in hormones and general growth cause breasts to develop. Most people consider the breasts fully developed by 18 years old; however, some development does still occur into a woman’s early 20s. Of course, there are also several other reasons that may cause the breasts to grow well after puberty.

Below are a few of the potential reasons your breasts may grow in your early 20s.

1: Hormonal Changes

Hormonal changes can occur for various reasons at any point during a woman’s life—the two expected and best-known ones being puberty and menopause. However, women may experience breast growth in their 20s due to fluctuating hormones. This can be natural—simply due to genetics or everyday life—but starting birth control can also impact the size of the breasts and cause them to increase in size. While not usually a large change, it may be noticeable for the individual.

As patients age and move closer to menopause, they will likely experience fewer hormonal changes not directly related to an identifiable cause. Normally, by their mid-to-late twenties, any unaccounted-for breast growth will likely begin to slow or cease altogether.

2: Weight Fluctuations

Weight fluctuations are normal during your early 20s. Firstly, many women gain weight in the early years of college and tend to lose it later. This can cause the breasts to increase in size as well. Additionally, losing weight can make the breasts smaller too. Some amount of weight fluctuation is perfectly normal as are the breast changes that may come with it.

3: Pregnancy

Many women become pregnant in their early 20s which will cause the breasts to naturally enlarge. This happens due to increases in hormones and eventually milk production. The enlargement seen during pregnancy and nursing is sometimes temporary but may lead to some permanent breast growth once no longer pregnant or nursing.

4: Development Of Fibrous Tissue

Fibrous tissue refers to benign, firmer tissue in the breasts. It may cause a feeling of bumps or lumps, but they are completely normal in this circumstance. Development of fibrous tissue may happen well after puberty and it can change the overall shape and size of the breasts. Most women have some amount of fibrous tissue, but some genetically will have more than others. This may cause a slight change in size, but patients a more likely to notice that their breasts may feel firmer, or they may feel a lump.


Breast growth in your early 20s is often nothing to worry about. Many women welcome the change and enjoy their fuller, womanly breasts. Patients who feel like their breasts are simply too small or underdeveloped can still obtain breast enlargement through breast augmentation surgery with Dr. Scott Blyer at Cameo Surgery Center. Saline implants are suitable for patients 18 years old and above. Silicone implants are approved for women 22 and older. This is due to the natural development cycle of breast-related things.

To learn more and schedule a consultation, call us at 631-232-2636. Patients can also reach out online via chat and contact form.

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Dr. Scott Blyer
Dr. Scott Blyer, also known as DrBfixin, is a Cosmetic Surgeon in NY with three board certifications and over 16 years of expertise. He honed his skills at institutions like Penn State, Stony Brook, and North Shore University Hospital and pursued an advanced fellowship in Texas.
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