Ask the experts

A pediatric endocrinologist answers your questions on puberty and more...

The purpose of Ask the Experts is to educate; answers are not meant to provide medical advice for any individual patient since the advice is given without knowing any specific medical information about your child, his or her allergies or current medications. The information provided should never be used as a replacement for direct and specific consultation with your child's doctor.

What is the normal age for breast development in girls?
My child is shorter than all of his classmates

What is the normal age for breast development in girls?

My daughter is 8-1/2 years old and just started breast development. Is this too early?
From: Julia, Wilmette

The earliest “normal” age that breast buds or pubic/axillary hair can be seen is starting at age 8 years. Prior to 8 years of age, any pubertal changes would be considered too early or “precocious” and would require further evaluation to assess for concerning reasons for pubertal activation. There are two different hormonal systems that drive breast development and pubic/axillary hair development, respectively. These changes usually appear around the same time but can they appear separately. Although studies have reported that up to 8-25% of girls in the U.S. were found to develop breast or pubic hair development before 8 years (with differing percentages based on race), pubertal changes that occur prior to 8 years of age should be evaluated for abnormal causes. Even if pubertal changes occur shortly after 8 years of age, changes that are rapidly progressive would require further evaluation. Initial testing typically includes evaluation of pubertal hormones and a bone age x-ray, which is a film of the left hand/wrist that assesses the body’s maturation.

My child is shorter than all of his classmates

My 12 year old child has always been short but now appears to be much shorter than all of his classmates, should we be worried?
From: Josh, Naperville, IL

A normal prepubertal growth rate is a gain of about two inches per year. If growth is continuing at a normal rate, it is less likely that a hormonal deficiency is involved.
Growth is determined by multiple factors including genetics and timing of puberty. Late bloomers often have a family history of late puberty and may follow along a lower growth percentile at a normal growth rate but “catch-up” at a later age since growth would continue for longer before the final height is reached. However, if the growth rate is slowing down or if the growth percentile is much lower than expected based on genetics, additional evaluation may be required.

Initial testing typically includes screening for hypothyroidism and growth hormone deficiency along with other conditions such as celiac disease. A bone age x-ray would also allow for assessment of whether the body’s maturation is delayed, which could be consistent with a late bloomer pattern; it also allows for calculation of a predicted adult height. This predicted adult height can be compared to the genetic target height which is determined by the parents’ heights to assess whether there is a concerning discrepancy that points to an abnormal cause.