Why Are Our Daughters Reaching Puberty Earlier And How Can We Help?

I think it's safe to say that every mother I know who has an elementary school-age girl took a much closer look at her daughter after Sunday's New York Times Magazine story on the apparent increase in early puberty among girls in the U.S.

The story raised many anxiety-producing questions, among them, why are girls starting to develop breasts and show other signs of puberty earlier — like at age 7 and younger — and what kind of harmful physical and emotional implications might all this have?

But the piece also had a few kernels of comfort, at least, for parents considering medical intervention for girls on the early side of "normal" puberty. Elizabeth Weill reports:

...Greenspan says this is a bad idea, because Leuprolide’s possible side effects — including an increased risk of osteoporosis — outweigh the benefits for girls that age. “If you have a normal girl, a girl who’s 8 or 9, there’s a big ethical issue of giving them medicine. Giving them medicine says, ‘Something is wrong with your body,’ as opposed to, ‘This is your body, and let’s all find a way to accept it.’ "

I asked Dr. Diane E. J. Stafford, a pediatric endocrinologist and training program director at Children's Hospital Boston about her thoughts on the story and what parents should know. Here is our short Q and A.

Rachel Zimmerman: If you have a daughter on the edge of "normal" say 7 or 8 and developing early, what should you, as a parent, do and should you consider medical intervention at that point?

Dr. Diane E. J. Stafford: It is important to remember that while the medical community is defining the “normal” range for breast development as after the age of 7 for Caucasian girls and after 6 for African American girls, this is a statistical norm and may not necessarily apply to all girls. We need to look at each case and determine if the timing is “appropriate” for that child. There are several factors that might prompt a referral for evaluation and possible treatment between 6 and 8 years of age. If a girl has a family history of delayed puberty (for instance, late menarche in her mother), short stature, behavioral factors that might make pubertal change an issue, significant headaches or visual changes (or other neurologic symptoms) or seems to have a rapid pace of progression, further evaluation may be warranted. This is both to determine if there is a pathologic cause, but also to determine if medical intervention should be considered.

Are there any non-medical interventions that might slow down development?

Once the cycle of true central puberty has started, there is nothing from a non-medical point of view that will change the pace. That being said, the pace can be different for each child, so it is sometimes difficult to predict. Obesity can increase bone age, likely due to increases in adrenal androgens and conversion to estrogens in fat. This can lead to a decrease in final adult height in some girls with early puberty. This is yet one more reason to try to decrease weight for those in this category.

Do you think that environmental factors are driving this increase in early development (and do you really believe there is an increase)?

If you look at the studies on which our prior definitions of the “average” age of puberty were based, they were poor in terms of ethnic variation and general statistical power. As such, it is hard to say if the most recent data supports a decrease in the age at which puberty occurs or is just defining this much better than previous studies were able to do. It is also true that there are many confounding factors to determining pubertal staging on the large scale basis that the 1997 and 2010 studies attempted and some people still take issue with this process. Many also point to the lack of change in the age of menarche identified by these studies (and in agreement with previously stated norms) as a signal that either the data is flawed or the implications are not as significant as is portrayed in the media.

In any case, if there is a true decrease in the age of pubertal development, it is likely due to multiple factors. As we don’t know the driving forces or “triggers” for the start of the cycle of puberty (pulsatile secretion of GnRH from the hypothalamus), it is extremely difficult to determine the influence of environmental factors. The onset of pubertal development and the variation from one child to another are likely influenced by environment (diet, chemicals, social interactions, etc.) as well as by physical health (obesity, other medical conditions) and genetics. The influences are so many and varied, that trying to control all these factors is truly impossible.