By Brenda Goodman
WebMD Health News
The age when girls start puberty is shifting.
In girls, puberty is a sequence of three events, breast development, the growth of pubic hair, and finally, a first period.
Recent large studies show that, on average, many girls’ breasts are budding about a year earlier than they used to.
This can have important psychological and biological consequences for young girls who aren’t mentally equipped to handle the changes.
Louise Greenspan, MD, a pediatric endocrinologist at Kaiser Permanente and the University of California at San Francisco has been studying this shift. She recently spoke at TedMed about her findings.
WebMD: What is early puberty?
Greenspan: When we talk about girl’s puberty, we’re not talking about when their period starts. From an endocrine or hormonal point of view, the period is actually a late step in puberty. What we’re really focusing on the first sign of puberty, which is breast development.
When I was in training and up until about 10 years ago, we used to say that girls’ breast development shouldn’t start at age 8, and now we’re saying it’s probably starting earlier. If we look overall at girls at age 7, 15% of girls have breast development at age 7 and it’s about 27% at age 8.
We used to say that age 8, fewer than 5% of girls should have breast development. So many more girls are going through early puberty as had in the past.
It doesn’t necessarily mean that first periods are starting earlier — so this is an interesting twist on this — it may mean that puberty is lasting longer, and the concern about that is that puberty is a window of susceptibility to environmental chemicals [including chemicals that mimic estrogen like BPA, some flame retardants and pesticides] and other stressors.
During puberty there’s a lot of growth — particularly of breast tissue, but of your whole body — and anything in the environment that might cause problems causes problems.
WebMD: Who is most at risk?
Greenspan: We looked at over 1,200 girls across the country over time, and what we were finding, in our study, is that at age 7, about 23% of black girls already had breast development, 15% of Hispanic girls and 10% of white girls already had breast development.
So the concern is that there are ethnic differences, with black girls starting puberty, on average, about a year sooner than white and Asian girls.
WebMD: Why is this happening?
Greenspan: I think there are three culprits. The evidence suggests that obesity is the main culprit. Severe psychosocial stressors is another one. They third is definitely probably something in our environment, some things in our environment — particularly endocrine disrupting chemicals.
I don’t want to minimize the concern over endocrine disrupting chemicals, but it’s the first thing people leap to. People leap to that without paying attention to the other two.
People leap to pesticides, and I’m not saying pesticides are OK — pesticides are harmful — but when it comes to puberty, there may be other things that are harmful.
WebMD: How does obesity contribute?
Greenspan: Fat tissue is actually a very potent endocrine or hormonal organ. Fat causes estrogen levels to be higher. It converts other hormones to estrogens, and estrogens are the hormones responsible for breast development, so we think this may start and trigger breast development and true puberty.
WebMD: What kind of stress are we talking about?
Greenspan: We’re talking about severe stress, such as victims of childhood sexual abuse. Children with extremely high levels of conflict in their families, children who live in extremely dangerous or violent environments.
We’re not talking about ‘Oh gosh, I argued with the children’s father over breakfast this morning over who is picking up the kids.’ We’re not talking about routine family arguments.
We’re really talking about toxic levels of family stress or severe stress in the environments that kids live in.
WebMD: How old is youngest girl you’ve seen with early development?
Greenspan: That’s a hard question because there’s a separate condition called Precocious Puberty, and those girls can be very young when they present. They can be 4 or 5. That’s not what we’re talking about here.
There used to be a pretty definitive separation between precocious puberty and true, normal puberty. The problem is if you have a 6 ½ or 7-year-old girl, does she have Precocious Puberty or early normal puberty? It’s made the job of people like me much more challenging.
WebMD: Do you treat early, normal puberty?
Greenspan: That depends on the situation, and it really depends on how old the girl is and how rapidly she’s progressing.
If she’s a healthy, normal girl with early puberty, we don’t leap to medical treatment.
WebMD: What are some of the consequences of puberty starting at younger ages?
Greenspan: Girls who go through puberty earlier are at higher risk for health concerns both as teenagers and adults. As teenagers, they’re more likely to have an eating disorder, they’re more likely to be depressed, they’re more likely to abuse drugs, and more likely lose their virginity at younger ages. As adults, they’re more likely to get breast cancer, they’re more likely to get heart disease and more likely to die earlier.
WebMD: Is there anything parents can do stop early puberty or is it something that we need to accept and help girls prepare for?
Greenspan: That’s really why Julie [Julianna Deardorff] and I wrote the book, The New Puberty. Because I think there are so many things parents can do, if not to prevent it, but to buffer their girls. One thing that’s important is that those downstream effects I just told you about are not inevitable if parents are knowledgeable and know how to talk to their children and what to do.
WebMD: Is it within our control, as parents, to stop early puberty?
Greenspan: Maybe. What is definitely within our control is to help girls have better outcomes.