Breast Development

My 10 yr old daughter has been developing in her left breast for about 10 months. So far, I have seen no development in the right breast and am wondering if there is cause for concern. Really , she is developing normally every where else. A little pubic hair and a little underarm hair. She has always been very healthy. Weighs around 80 lbs and is in the 90th percentile for her height. She has not started menstruation and probably will not for about another year, I am guessing.
Should I be concerned that the right breast is not developing yet? Is this common?

[Deanna L Aftab Guy, MD]

Assymetric breast development is common, however if there is no tissue on one side due to her being born with atrophy of that area this might also explain it, I would have your pediatrician monitor her every 4-6 months and if needed they can consider referral