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What are the causes of asymmetrical breasts?

There are various factors which can cause asymmetrical breasts, including genetics, hormonal changes, trauma and puberty.

Tagged: Body & Breast

Author: Mr. Bryan Mayou, MB ChB FRCS

Date: 11th December 2020

Medically Reviewed by:  Mr. Bryan Mayou (GMC: 1414396)

Last reviewed: 7th February 2024

What is Breast Asymmetry?

Breast asymmetry is a common feature among women in which there is a natural variation to the size, shape or position between their breasts. 

Breasts come in all different shapes and sizes and full symmetry is rare. It is estimated that the majority of women have at least some minor degree of breast asymmetry.  

Asymmetry can become visible for several key reasons: 

  • Difference in breast shape e.g. one breast is anatomically round in shape and the other is droopy 
  • Difference in size and volume (Anisomastia), e.g. one breast is visibly larger than the other or fuller, perhaps by a cup size  
  • Nipple / Areola Variation (Anisothelia): the size, position or shape of the nipples and areola varies e.g. one nipple is flat or inverted, and the other is protruded or puffy   
  • Breast Positional variations: the position of each breast on the chest wall varies between the breasts 
  • Combined Asymmetry in which any one of the above breast asymmetries is combined with another 

Is Breast Asymmetry Normal?

Breast asymmetry is considered normal and very common among women when it is mild. 

More severe breast asymmetry in which discrepancies are more pronounced are less common however, and may lead to a sense of physical discomfort or emotional distress. In such instances they may choose to consider cosmetic or reconstructive surgeries to restore a more balanced aesthetic.   

It is important to speak to a qualified plastic surgeon if this is the case. 

What Are the Causes of Asymmetrical Breasts?

There are various factors that can cause asymmetrical breasts, including genetics, hormonal changes, trauma and puberty.  
Breast tissue can also change during ovulation, leaving the breasts feeling fuller and more sensitive. It is not unusual for breasts to look bigger during this stage in a woman’s menstrual cycle because of water retention and blood flow. They return to normal size during menstruation. 

A condition called juvenile hypertrophy of the breast can cause one breast to grow significantly larger than the other. This is a rare condition that can often have a negative impact on a woman’s mental health. This can be corrected with surgery. 

Other common causes of asymmetrical breasts include significant weight gain or loss, hormonal changes during pregnancy and the physical impact of breastfeeding.  

It is also common that previous breast surgeries such as breast augmentation, breast reduction or mastectomy can result in breast asymmetry.  

What Breast Asymmetry Surgeries Can Restore Breast Symmetry?

Several breast asymmetry surgeries can make your breasts symmetrical. These breast asymmetry correction surgeries include:  

Breast Augmentation
Increases the size of your smaller breasts with the use of an implant. A quick and effective procedure  

Breast Lift/Mastopexy  
This procedure can help to improve shape and symmetry, with minimal changes in breast volume. Breast uplifts are typically performed without implants and involve the repositioning of the breast and nipple higher on the chest wall, , whilst removing any excess skin, to deliver more youthful breast shape by raising the nipple and removing excess skin.  

Fat Transfer to Breast 
Lipofilling or fat grafting to the breast will lift the breasts in a similar way to using implants by adding volume but is done via the injection of fat and without implants and can achieve more subtle contoured results. There is the has the added advantage of including liposuction to harvest the fat as part of the operation to achieve a better contour elsewhere on the body.  

Breast Reduction 
Reduces the size of the larger breast by removing excess breast tissue and reshaping the larger breast to match the smaller one  

Breast Lift plus Augmentation
Addresses both a size and sagging imbalance by combining a breast lift with implants to deliver a fuller outcome 

Breast Implant Replacement
Exchanges old implants with new ones to restore symmetry  

Nipple Correction Surgery
Addresses any variations in nipple size, shape, position or protrusion. Might include a nipple reduction, augmentation or areola reduction  

Breast Reconstruction
Typically performed post mastectomy to recreate one or both breasts in a balanced shape.

Here at the Cadogan Clinic in London, one of our expert surgeons will assess which breast asymmetry correction surgery is best to correct the breast asymmetry during a consultation in advance of your procedure. 

How Much Does Breast Asymmetry Surgery Cost?

Breast Asymmetry surgery costs vary depending on which breast asymmetry correction surgery is chosen by your surgeon. 

Our breast surgery starts from £5,900 at Cadogan Clinic. 

Can I See Breast Asymmetry Before and Afters?

Yes, you can see some examples of breast asymmetry before and afters in our breast enlargement gallery.  

Your surgeon can supply additional images at your consultation, as can our Patient Advisor team if you call 0207 901 8500.  

What Does Asymmetry in Breasts Mean?

Breast asymmetry means one breast has a different size, volume, position, or form from the other. Breast asymmetry is very common and this condition affects more than half of all women. 

Many women have concerns that breast asymmetry may mean they have cancer, and some studies have indicated that women with breast cancer do have a greater breast asymmetry than healthy women, perhaps by as much as 20%.  

Whilst uneven breast sizes are a common occurrence and are typically not a reason for worry, we do recommend that to properly safeguard your breast health that you seek medical advice if you do notice a sudden alteration in breast density or a significant increase in breast asymmetry, as it may potentially signal breast cancer. 

We also recommend undergoing routine mammograms as a standard practice. Early detection through mammography ensures prompt identification and treatment of any irregularities, and we recommend regular mammograms as a healthy component of regular breast health monitoring. 

Why Are My Breasts Different Sizes?

There is no single reason why your breasts are different sizes. This could be due to genetics, lifestyle factors such as weight gain or weight loss, pregnancy and breastfeeding, or trauma and previous breast surgery.

What If One Breast is Lower Than the Other?

It is completely normal if one breast is lower than the other and very common for a woman to have one breast hanging slightly lower than the other one. This is not usually a cause for concern.

However if the degree of the variation bothers you or the size of your breasts changes or the density variation becomes larger over time, it would be a good idea to speak to a medical professional.

Can Menopause Cause Breast Asymmetry?

Breast asymmetry is not directly caused by menopause and is far more likely to be caused by genetics and age in women experiencing menopause than menopause itself. 

However, during menopause, hormonal changes do occur as the female body transitions out of the reproductive phase. These changes can have an effect on breast tissue, although they do not commonly cause significant breast asymmetry.

Can I Get Breast Asymmetry Surgery on the NHS?

The vast majority of breast asymmetry correction surgeries are performed privately in the UK. 

In rare cases where there is a medical necessity, it might be possible to get your breast asymmetry surgery on the NHS in the UK.  

Eligibility and criteria vary by geography, and timelines may be long. No cosmetic procedures are performed on the NHS, so you will need to prove physical discomfort, psychological distress, or other medical issues.  

What Are Tuberous Breasts and How Can They Be Corrected by Breast Asymmetry Surgery?

Tuberous breasts are a congenital condition where the breasts have a narrow base and are elongated in shape with a slightly higher inframammary fold, resulting in a less rounded tubular breast appearance.  

Tuberous breasts can affect one or both breasts and are a common feature of breast asymmetry cases. Correcting them requires a specialist approach, with most surgeries relying on more subtle fat transfer breast augmentation techniques to restore volume and contours, particularly in the lower part of the breast. This typically delivers the most natural result.

Words From Our Founder

Mr. Bryan Mayou

Asymmetric breasts is a common concern among women and can have various causes such as genetics, hormonal influences, or previous surgeries. Our approach to breast surgery prioritises bespoke treatment, addressing each patient's individual concerns. Whether through Breast Augmentation with different implant sizes or Mastopexy with customised repositioning, our surgeons will always aim to achieve balanced and natural results. By tailoring procedures to the specific needs of each breast, we restore symmetry and confidence.
Mr. Bryan Mayou

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