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Sieber Plastic Surgery San Francisco

Top Breast Asymmetry Reasons


Many women like the idea of having larger breasts while others are happy with modestly sized breasts or even small breasts. But it’s nearly unheard of for any woman to be happy with asymmetrical breasts.

Not only can this issue be embarrassing and uncomfortable, but it can also be disconcerting. What are the causes of breast asymmetry? you wonder. Could it be a problem with my implants? A hormonal imbalance? Breast cancer?

Below, we’ll go over the top breast asymmetry reasons, then discuss some of the best ways we treat asymmetrical breasts if this issue has been bothering you.

Top Reasons for Uneven Breasts

#1 – Pregnancy

As a woman’s body goes through the stages of pregnancy, her breasts may change drastically — usually becoming larger. This is the body preparing itself for breast milk production with the secretion of prolactin and the growth of breast duct cells.

#2 – Breastfeeding

If a woman is breastfeeding her baby after childbirth, the size and shape of her breasts will vary significantly from week to week, day to day, and hour to hour — depending on how much milk she is carrying and needs to produce at any given time.

#3 – Puberty

Certain young women may develop breast asymmetries during puberty. These changes usually resolve quickly, and the breasts become evenly shaped and sized as the puberty stage ends.

#4 – Menstruation

During menstruation, changes in hormones may cause the size or shape of one or both breasts to change. Like puberty-related changes, these are usually short-lived, and the breasts will regulate in volume after a few days or weeks.

#5 – Injury or Trauma

Injury to a single breast is one of the main reasons for sudden asymmetry in breast growth in adult female individuals. Some injuries can cause cysts or swelling, for example. This may be after a car accident, a fall, or even during or after a significant illness.

#6 – Normal Changes Due to Aging

Certain women simply experience varied breast shape as they age. Gravity, posture, sleeping position, exercise routines, and other common daily activities can slowly alter the way the breasts sit on the chest wall.

#7 – Implant Issues

Finally, if a woman has breast implants, she may experience uneven breasts due to capsular contracture in one breast or a leaking or ruptured implant. This is more common with saline implants, as when a saline implant ruptures, the fluid may leak entirely out, leaving a noticeable difference in breast size.

Breast Asymmetry on Mammogram Reasons

Reasons For Sudden Asymmetry In Breast Growth In Adult FemaleOccasionally, women will go for their annual mammogram and receive results that indicate asymmetrical breasts. This is a cause of concern for many women, who obviously worry that a  mammogram results with breast asymmetry could mean breast cancer or another serious medical problem.

Often, mammogram results will indicate that asymmetries are related to density, breast tissue volume, or structure. In fact, any of these asymmetries are fairly normal and not a sign of developing breast cancer. Nearly all of the time, asymmetries in mammogram results are benign.

In fact, what an asymmetrical result is indicating is that a specific area on one breast is different in some way from the same area on the other breast. The difference may be calculated with a number indicating the relative breast volume asymmetry value. In these cases, radiologists will often order additional tests (a breast biopsy or breast ultrasound, for example) or follow-up mammograms to be sure that any asymmetries are benign.

Usually, the differences have to do with a change in size, volume, or form over time. More rarely, mammogram machinery and technology may be faulty. Again, it is uncommon for breast asymmetry to be a sign of breast cancer. Usually, other symptoms such as flaky red skin around the nipple, dimpling irritated breast skin, swollen breasts, or distinct breast lumps are the notable signs of possible breast cancer.

If you ever have questions about an asymmetrical mammogram or the possibility of breast cancer and your personal cancer risk, never be afraid to consult your doctor or radiologist about follow-up tests. Breast cancer research is constantly improving and evolving to save more lives.

How Is Breast Asymmetry Treated?

Breast Asymmetry ReasonsThe good news about most cases of uneven breasts is that the issue can be treated with reconstructive surgery. However, the first thing we always want to do when a patient comes in with uneven breasts is to make sure that there’s not a worrisome underlying cause. 

For this reason, we like to have a consultation appointment with you where we can discuss your medical history — and possibly schedule some additional medical tests for you to ensure that your breast asymmetry is not caused by an underlying condition that needs to be treated.

Once we’ve done that and the cause of asymmetry is benign and not requiring treatment, we can discuss the various ways to correct your asymmetry and give you breasts that look full, natural, attractive, and — most of all — symmetrical. With breast asymmetry surgery, it always depends on the patient and the particular situation each patient is in with her breasts. The following procedures are the options we usually turn to when correcting breast size asymmetry:

Breast Augmentation (Breast Implants)

A breast augmentation using breast implants is one of the most common procedures performed to correct breast asymmetry. In fact, it is often performed after a prior unsatisfactory breast augmentation as a breast augmentation revision surgery.

During this procedure, a small incision is made in the breast, and a saline or silicone implant is inserted to add volume. Breast implants run the gamut from large and voluminous to very small and natural-looking. You will have plenty of time to discuss your implant options with Dr. Sieber and his staff.

Breast Fat Transfer

Breast augmentation fat transfer surgery is a two-stage process that first involves using liposuction to take out unwanted fat from one (or multiple) areas of the body (usually the abdomen). The second step is the re-injection of that fat (after it has been processed outside the body) into one or both breasts.

Breast Lift

Sometimes, the position of a breast on the chest wall is thus that it sits lower than the other breast. This can be corrected with a lift to one or both breasts.

A breast lift, also known as mastopexy, requires an incision to be made around the areola (the darker part of the skin that surrounds the nipple) and usually, an incision to be made from the lower part of the areola down to the crease beneath the breast. Sometimes, an additional incision is made along the crease. Then, excess skin, fat, and breast tissue is removed, and the incisions are closed up.

Breast Reduction

Finally, if the patient is interested in bringing the size of the larger breast down, a breast reduction can be performed.

Some patients with asymmetrical breasts may want to simply perform a breast reduction on one breast to make it the same size as the other, smaller breast. Other patients may want to reduce the overall size of both breasts and because of the asymmetry, this may involve removing more fat, breast tissue, and skin from one breast, in particular.

Uneven Breasts? Schedule a Consultation Today

Do you have uneven breasts that look and feel asymmetrical in volume, shape, or position? Double board-certified plastic surgeon Dr. David Sieber can help.

Contact us today to book a consultation to discuss breast asymmetry surgery with Dr. Sieber. We look forward to your call. 



Dr. Dave Sieber and his staff are so awesome! Dr. Sieber is personable yet professional, his work is impeccable. He listens to his patient and works with them to achieve what they want. He’s like my hair dresser, a magician, you just want to do a happy dance with the results, only these results are lasting. Ok, but seriously, the procedure was very smooth, the staff and the doctors (Dr Sieber and the anesthesiologist) had great communication and made sure I was comfortable with very clear and concise pre op and post op directions. The healing process was very easy and the results are FABULOUS. Side note, Dr. Sieber has really awesome skin, I feel like this is impressive and important because really, would you trust a dentist with bad teeth? I am so elated and satisfied with the results, the size is perfect and they look and feel very natural. They are exactly what I wanted.*

SF Scientist

Dr. Sieber is a doctor who is not only extremely knowledgeable about the latest in cosmetic procedures, but a doctor who truly cares about his patients. I highly recommend him!*


Dr. Sieber is a doctor who is not only extremely knowledgeable about the latest in cosmetic procedures, but a doctor who truly cares about his patients. I highly recommend him!*


Dr. Sieber is attentive, responsive, and well trained. I had seen him for Botox and filler and he had done both without any pain or bruising and more importantly the results were fabulous. He has met with me on time at each appointment. He communicates what to expect, made sure I was comfortable throughout the procedure, checked on my healing every day post procedure. He couldn’t be more delightful not more talented. I had seen other plastic surgeons for in office treatments over the past decade and Dr. Sieber is at the top of the list in terms of delivering the desired outcome and high quality care.*

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