HomeWhat Are The Causes Of Large Breasts?

What Are The Causes Of Large Breasts?

Breast size is determined by a combination of genetic and environmental factors. While breast size is subjective and can differ from one culture to the next, large breasts that cause physical and psychological problems may require treatment.

If you suffer from excessively large breasts that have either grown gradually over time or suddenly developed in weeks, you may be wondering why. Often medically referred to as macromastia, large breast growth can be alarming for some, especially if the breasts grow suddenly without any clear explanation.

Within the article below, you will discover the main causes of large breasts and the most effective treatment options currently available.

Living With Large Breasts

Although less endowed women might dream of having large breasts, the reality of living with excessive breast tissue and macromastia can be less than enjoyable than many might assume.

With common side effects of large breasts, including breast pain, back pain, neck pain, and shoulder pain, as well as mental implications such as social anxiety, low self-esteem, and depression, living with large breasts can have a huge impact on your overall quality of life.

Fortunately, you don’t need to live with the pain and discomfort of excessively large breasts; treatment options are available.

What Causes Large Breasts?

There are several possible causes of large breasts, some of which are more common than others. Let’s take a closer look at each potential cause of excessive breast growth and macromastia as a condition below so you can find out what might have caused your large breasts.


Genetics play an important role in breast size, so if you have a family history of large breasts or macromastia, you are much more likely to have them as well.

It is worth noting that larger breasts can be inherited from both your mother and your father’s side, which means it is worthwhile looking into both sides of the family to determine if genetics cause your large breasts.

Hormonal Changes

A woman’s breasts typically develop during puberty as the estrogen in the body increases. Pregnancy and breastfeeding can also cause the breasts to increase in size due to hormonal changes.

However, large breasts caused by pregnancy or milk production should return to normal relatively quickly after giving birth or stopping breastfeeding. If your breasts do not return to their normal size, the cause of your large breasts may be something else.

Drugs and Medications

Both prescription and illegal drugs can affect the size of your breasts, with larger breasts occurring in both men and women through drugs and medication use. Most typically, men may develop more breast tissue due to taking marijuana or anabolic steroids.

Other drugs, including bucillamine and neothetazone, can cause macromastia and excessive breast tissue in women. If you think your medication is causing your large breasts, talk to your doctor about alternative medicines that do not cause this side effect.

 Weight Gain

If you have recently gained weight, this may cause your large breasts. The breasts are made up of fatty and glandular tissues, so any weight gain will likely cause them to grow.

Weight loss can also affect the size of your breasts, although you should see a size reduction when you lose body fat.

Macromastia As A Condition

As mentioned, macromastia, also referred to as ‘breast hypertrophy’ or ‘gigantomastia’, is a rare condition that causes excessive breast tissue growth. Although this typically occurs during adolescence, it can happen to women of all ages.

There is no one cause of macromastia, and in most cases, it appears to occur randomly. If you think you may have this condition, book an appointment with your doctor to receive an official diagnosis and discuss your treatment options. 

Birth Control

The hormones present in most birth control medications can change the size of your breasts. This can happen very quickly but is nothing to be alarmed about.

If you have recently started taking a new birth control pill and your breasts have suddenly grown in size, you may want to wait a few weeks to see if they return to normal once your body gets used to the medication.

If your breasts remain overly large and are causing you pain or discomfort, speak to your doctor about switching birth control.

Medical Complications

Certain medical conditions can cause your breasts to become enlarged and lead to macromastia. This can occur gradually or in a matter of weeks. Benign breast cysts and benign tumors can sometimes be large enough to affect breast size and lead to the appearance of fuller breasts.

If you suspect that this may cause your large breasts or you are experiencing any pain or swelling, make an appointment with your doctor as soon as possible.

Large Breasts – Surgical Treatment

Another option is surgery if your large breasts cannot be treated with medication or by making lifestyle changes. 

Breast reduction surgery, also known as reduction mammaplasty, is a popular treatment option for women who suffer from macromastia and excessive breast tissue. This procedure typically involves the removal of between 400 to 2000g of breast tissue and skin tightening known as mastopexy.

After having this surgery, most patients notice a significant improvement in their associated symptoms, including headaches, breast pain, and back pain. However, it is worth noting that this surgical procedure is not without complications, so you must ensure that this is the right choice for you and your body.

You can read more about how reduction mammaplasty works in the clinical research of Claudia Maria Santos Aldrighi, who works at the University of Sao Paulo School of Medicine in Sao Paulo, Brazil.


 If you are unsure what has caused your breasts to grow in size or are worried about the sudden enlargement of your breast tissue, the best course of action is to book an appointment with your doctor.

They will be able to perform a physical examination of your breasts and diagnose macromastia if it is indeed occurring, as well as talk through your medical and family history. In most cases, no further testing is needed.

Once you have established the cause of your large breasts, you can discuss your treatment options. If you’re interested, you can read more about macromastia and other medical conditions at KOLs.

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