1 big 1 small breast why ?

Asymmetrical breasts are quite common. She still has many years of breast growth ahead of her. You should see your GP or pediatrician to ensure that there are no congenital or endocrine issues. 

Thank you for your question! This is actually a fairly common situation in young woman that can be treated surgically... One would either reduce the larger breast to match the smaller or place an implant in the smaller breast to match the larger. The breasts may still be growing so you could choose to wait... however, depending on how much it bothers her, she can proceed with intervention at any time. Good luck!

Unfortunately, in most cases there are no specific reasons why there is breast asymmetry. In a rare cases such as Poland's syndrome (also absent pectoralis muscle and webbed fingers on one side) or trauma like burns on the breast can also prevent later develoment

Thank you for the question.These cases are common in a lot of women, asymmetrical breast can be corrected. Your daughter is still growing, so I wouldn't be concerned right now but it might be an issue to look for in the future.Good luck,Dr. Campos

It is not unusual to have some asymmetry in the breasts. If there is a very large difference that persists throughout her development, it is possible that she might have tuberous breast deformity or some other congenital problem that is mostly aesthetic. Other causes to poor breast development on one side can be a burn, surgery, or trauma to a breast at a young age. No need to be too concerned now, but you should speak to your pediatrician for more information. I would not advise surgery for cosmetic reasons on any person this young.

As if going through puberty isn't enough for a teenager this certainly doesn't help with her self esteem.  It is not unusual for one breast to develope faster than the other and very early on the differences are exaggerated.  At 13 I would not recommend doing anything other than possibly seeing a plastic surgeon to reassure her that even if they don't even out there are things that can be done when she is a little older and physically more mature.  Speak to her pediatrician for a recommendation if you are out of this area.  Good luck, Dr. Schuster in Boca Raton