Unpacking Benign Breast Asymmetry

While it is commonplace for women to have one breast that is slightly different from the other, some women have more marked differences in the size, shape, or position of the breasts – even after development is complete. This often leads to negative effects on their emotional well-being and self-image. Dr Isabel do Vale discusses the psychosocial benefits of plastic surgery for young women with benign breast asymmetry.

A recent study in the October 2020 issue of Plastic and Reconstructive Surgery (the Journal of the American Society of Plastic Surgeons) shows that surgical treatment of breast asymmetry in young women results in significant improvements in quality of life and psychological well-being1.

The study by Dr Brian I. Labow, MD, FACS, FAAP, and colleagues of Boston Children’s Hospital, is possibly the first study to prospectively review the benefits of surgery for benign breast asymmetry. After a nine-year follow-up period, the researchers showed that significant benefits resulted, specifically in the social functioning, mental health, self-esteem as well as work and activity-related physical functioning of young women who underwent surgery to address benign breast asymmetry1.

So what is benign breast asymmetry? What causes it? And how can it be treated or corrected?

Benign breast asymmetry is a broad term that really simply means there is a difference between an individual’s left and right breasts, relating either to breast size, shape and/ or position. Minor degrees of breast asymmetry are common, with almost all women do have some breast asymmetry – especially in the early stages of breast development – but these asymmetries often also persist beyond puberty. Less commonly, some teenage girls experience moderate to extreme differences in breast size or appearance. These more extreme breast differences might be caused by acquired or congenital breast conditions such as:

  • Tuberous breast deformity (a congenital anomaly also known as constricted breasts, in which the lower quadrants of the breast are under-developed, where there may be herniated areola complexes which appear enlarged or ‘puffy’ compared to the rest of the breast)
  • Poland syndrome (a disorder in which affected individuals are born with missing or under-developed muscles on one side of the body, affecting the chest, shoulder, arm, and hand. The breast may be under-developed or absent on the affected side.)
  • Unilateral macromastia (an overly large breast on one side)
  • Unilateral breast hypoplasia (one breast is under-developed)
  • Polymastia (the presence of an additional breast. Extra breasts may appear with or without nipples or areolae.)
  • Polythelia (the presence of an additional nipple alone, usually in line with the normal breast, along the milk line)
  • Amastia (complete absence of the breast tissue, nipple and areola)
  • Amazia (the mammary gland is absent but the nipple and areola are present)
  • Rib-cage abnormalities
  • Traumatic injury
  • Posture / spinal issues

When a significant breast asymmetry exists it may persist beyond adolescence and can lead to significant psychosocial distress. Most benign forms of breast asymmetry begin during adolescence, unfortunately at a time when general body concerns are common, often along with impaired self-esteem of some degree. These young women may avoid certain situations such as sports participation, extra-murals, swimming, gym activities or even tight-fitting clothing that may risk their breast asymmetry being noticed by others.

They might become increasingly self-conscious, withdrawn, experience reduced psychological well-being and general health-related quality of life. The Boston children’s hospital study, notably shows that breast asymmetries do significantly impact the quality of life of affected young women. Furthermore, the study also shows that surgical correction of benign breast asymmetry yield sustained improvements in psychosocial quality of life, which should not be overlooked1.

Treatment of breast asymmetry

There are several safe and effective plastic surgical procedures that can be used to correct benign breast asymmetries. Depending on the extent and severity of asymmetry, addressing breast asymmetry can occasionally be a complicated process, which may depend on multiple factors.

These include the extent and severity of asymmetry, specific characteristics/ abnormalities of the breast(s), and in the case of adolescents, the stage of breast development, as well as the age and psychological maturation of the patient.

Usually, a good starting point is a reassurance and an explanation that some degree of breast asymmetry is common (and normal among most women), especially in puberty. This may be sufficient for patients with lesser degrees of asymmetry.

Where asymmetry is more drastic, it must be noted that there is value in waiting for breast development to be complete or stabilized before pursuing surgical correction. While waiting for the breasts to stop growing and the size to stabilize, a breast prosthesis can be used under clothing to mask the asymmetry.

For young women in whom breast development is complete surgical correction may involve

  • Breast augmentation with an implant, to enlarge the smaller breast,
  • Breast reduction to decrease the size of the larger breast,
  • Fat transfer from another body site to the breast (typically used for smaller degrees of asymmetry)
  • Breast lift surgery (known as a mastopexy) to correct the position of one or both breasts
  • A combination of the above procedures may be required in some cases.

Women with breast asymmetry may avoid certain situations such as sports participation, extra-murals, swimming, gym activities or even tight-fitting clothing that may risk their breast asymmetry being noticed by others.

It’s important to note that sometimes correcting breast asymmetries could require more than one procedure depending on the specific needs of the patient. Women seeking surgical correction of benign breast asymmetries should schedule a consultation with an APRASSA member Plastic Surgeon. A qualified plastic and reconstructive surgeon will perform a full examination, the necessary investigations and will appropriately counsel the patient regarding all available treatment options, procedures and the recovery process.

A note on breast asymmetry and cancer:

Breast asymmetry is not typically a symptom of breast cancer. However, any woman who notices any sudden changes in breast symmetry should see their doctor and undergo a mammogram to rule out cancer. Non-cancerous fibroids, benign breast tumours, or breast cysts can also result in gradual or sudden changes in breast size or shape.

Written by Dr Isabel Do Vale

This article was written by Dr Isabel Do Vale and edited by the A2 team EXCLUSIVELY for the A2 Aesthetic & Anti-Ageing Magazine Summer 2020 Edition (Issue 35 – Dec 2020 to Mar 2021). 


  • Labow, Brian I. M.D. et al. The Effect of Surgical Treatment on the Quality of Life of Young Women with Breast Asymmetry: A Longitudinal, Cohort Study. Plast Reconstr Surg: October 2020 – Volume 146 – Issue 4 – p 400e-408e
  • Nuzzi LC, Cerrato FE, Webb ML, et al. Psychological impact of breast asymmetry on adolescents: A prospective cohort study. Plast Reconstr Surg. 2014;134:1116–1123.
  • Chan W, Mathur B, Slade-Sharman D, Ramakrishnan V. Developmental breast asymmetry. Breast J. 2011;17:391–398.

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