Why Are my Breasts Uneven? Causes of Asymmetrical Breasts

Do your breasts appear uneven? Is one more lopsided than the other? You’ll be surprised to know that asymmetrical breasts are extremely common in women. This is when your breasts appear different in size, shape or position, even with fully developed breasts this can be normal. The causes of asymmetrical breasts can be genetically driven which means if your family members had naturally lopsided breasts it would have been passed down to you too. You can notice signs of asymmetrical breasts as early as puberty. Early stages of breast growth can show indications that one breast is growing larger than the other. The reasons for this can be unclear as it’s most likely to do with the growth of the skin tissue. The tissue growth may be more on one side compared to the other or the cells are more sensitive to hormone levels of estrogen. Over time, the smaller breast will catch up but it can take a while before it catches up.

Medical causes of asymmetrical breasts

Medical conditions can be the common causes for asymmetrical breasts and below outline what these could be:


When you go through pregnancy, your breasts can appear to look asymmetrical. This can be caused from the natural hormonal changes that your body goes through during pregnancy and also the body preparing you for breastfeeding. This can make your breasts appear larger and different in shape or size. When you breastfeed, your baby may prefer being nursed from one side more than the other causing the breasts to vary in size. This isn’t something to worry about, however, as the most important thing is that your baby is getting enough milk for them to grow.

Hypoplastic Breasts

Hypoplastic breasts are commonly known as underdeveloped breasts. The symptoms for this are when the breasts appear rather wide apart, small and thin. There will also be a noticeable appearance in your areolas where they appear large on the small breasts. The cause for this condition is relatively unknown, but it’s believed that this is something that can be caused by hormone production. Another cause can be from injury.

Juvenile Hypertrophy

This is a rare condition and results in one breast growing significantly larger than the other. It’s not completely known what the cause of this is but it can revolve around hormonal production and your body’s sensitivity towards it. If this does occur, the condition can be treated via surgery.

Atypical Ductal Hyperplasia

Familiarly known as ADH, this is a condition where excessive growth tissue forms in the breasts milk ducts. Although ADH isn’t a form of cancer you should be aware that it can still increase your risk of developing cancer in the future. The appearance of your breasts can change due to lumps forming from the condition. This is because more cells develop around the duct line which can be differential in shape and size.

Should I be worried about uneven breasts?

Asymmetrical breasts are relatively common in women, so it shouldn’t be too much of a concern. However, there are studies that suggest asymmetrical breasts can be a risk factor for breast cancer. This is not for certain as more studies need to be conducted to determine whether this is a big enough risk factor for cancer. In the meantime, if you do notice any differences in your breasts within shape and size, inform your doctor.

Coping with asymmetrical breasts

As we’ve outlined throughout the post, asymmetrical breasts are relatively common and shouldn’t be anything to worry about. However, coping with uneven breasts in everyday life can become a problem, particularly when choosing everyday attire. If this is something that is a concern for you, professional bra fitters are available to help conceal this. Alternatively, asymmetrical breast surgery is available here at Gary Ross. There are different techniques that can be used to help provide you with your preferred appearance for your breasts. We do advise that you consult with your doctor first before considering asymmetrical breast surgery. For more details about the surgery and how it’s conducted, be sure to visit our procedure page.

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