What Causes Breast Asymmetry?

It is not unusual for women to critically assess their bodies in the mirror. This can be a way to check on any significant changes in the body, particularly in the breasts. Many women may notice that their breasts may not have the exact same size, shape, or placement on the chest. Although all women will have some variance between their breasts, it can be very prominent in some cases. Our staff at Jefferson Plastic Surgery is often asked about the causes of breast asymmetry, as well as what can be done to address it.

Is Breast Asymmetry Normal?

Our bodies are not completely symmetrical. We may have one leg slightly longer than the other, or one arm slightly shorter. The same is true of the breasts. In fact, more than half of women have some form of breast asymmetry. However, there are some instances in which the breasts are noticeably asymmetrical. This is particularly evident if the breasts are one or more cup sizes in difference in size.

What Can Cause Breast Asymmetry?

Hormonal fluctuations: Aside from just natural differences in breast size, shape, and position, the most common cause for asymmetry is hormonal imbalance, generally if the body produces too much estrogen. Although there might be slight variation just before the menstrual cycle, breasts of noticeably different sizes are common during adolescence.

Breastfeeding: Although various lactation resources say to nurse an infant on each breast evenly, it is not unusual for the child to have a preference for one breast over the other. Because of this, the preferred breast will stay larger than the other one, as it is continuing to produce more milk. Once the child is no longer breastfeeding, the preferred breast will also often sag or droop more than the other one.

Hand dominance: As strange as it may seem, a woman’s hand dominance may actually cause breast asymmetry. Hand dominance is one indicator of which side of the body we use more frequently. If a person is right-handed, for example, the right shoulder and arm muscles will be more developed, along with the pectoral muscles on the right side of the body. Although the breasts themselves do not have any muscle structure, the condition of the pectoral muscles can affect the position of the breast on the chest wall.

Body alignment: In addition to not having bodies that are perfectly symmetrical, our bodies are also not always perfectly aligned (meaning that the spine is in the correct position). The body can move out of alignment due to illness, stress, poor posture, or injury. This will cause the muscles to develop in such a way as to attempt to compensate for the misalignment. Similar to hand dominance, a misalignment of the body can also affect the size, shape, and position of the breast.

It is very easy to be overly critical of our bodies. In the case of breast asymmetry, it is usually so small as to not be noticeable. However, our staff can help if you do decide to undergo surgery to address breast asymmetry. 

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Jefferson Plastic Surgery is located on the corner of 9th and Walnut streets in Center City, Philadelphia on the 15th floor of the Wills Eye Hospital Building.

Jefferson Plastic Surgery
840 Walnut Street - 15th Floor
Philadelphia, Pennsylvania 19107
Phone: (215) 625-6630
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