Girls who hit puberty early
might be more likely than their peers to get into fights or skip school, a new
Researchers found that
girls who started their menstrual periods early – before age 11 – were more
likely to admit to a "delinquent act". Those acts included getting
into fights at school, skipping classes and running away from home.
Early bloomers also seemed
more susceptible to the negative influence of friends who behaved badly, the
researchers said in the online issue of the journal Paediatrics.
This study is not the first
to find a connection between early puberty and delinquency, but none of the
findings can prove that early maturation is definitely to blame.
"There could also be
other reasons, such as family structure and socio-economic status, that may
drive both early puberty and problem behaviours," said lead researcher
Sylvie Mrug, of the University of Alabama at Birmingham.
Mrug said her team tried to
account for factors such as family income, and early puberty itself was still
tied to a greater risk of delinquency. So it's possible, Mrug said, that early
maturation affects girls' behaviour in some way.
On the other hand, she
said, one theory is that there is a "mismatch" between physical
development and emotional development in kids who start puberty earlier than
"These girls look
older and are treated by others as older, but they may not have the social and
[thinking] skills to deal with these external pressures," Mrug said.
"It is typical for
girls with early breast development to be treated differently," said Dr
Frank Biro, a professor of clinical paediatrics at Cincinnati Children's
Hospital Medical Centre, in Ohio.
This study defined early
puberty based on menstruation, but breast development comes first. It's the
sign of maturation that other people can see, Biro said.
Earlier breast development
Research also suggests that
American girls today typically develop breasts at a younger age than in past
decades. In a recent study, Biro found that black girls typically begin
developing around age 8, while white, Hispanic and Asian girls start around age
Among white girls in
particular, that age has declined since the 1990s, Biro said. The main reason,
his study found, was the rising rate of childhood obesity.
Some researchers are
concerned about that trend because of studies like Mrug's, which link earlier
development to certain negative effects – particularly in girls, who have been
studied much more than boys.
Biro said earlier puberty
in girls has been tied to earlier sexual activity, depression and problems with
body image and self-esteem. "Just because you look physically more mature
doesn't mean you're developing any quicker emotionally and socially," he
These latest findings are
based on 2 600 girls from three US cities who were followed from the ages of
11 to 16. Overall, 16% said they'd started menstruating before age 11
and were considered "early maturers".
In general, those girls
reported more acts of delinquency at ages 11, 13 and 16. The average
difference, however, was not dramatic. At age 13, for example, early bloomers
admitted to one delinquent act in the past couple years, versus an average of
0.5 for other girls.
Parents don't have to be
worried that their daughter is destined to run wild just because she developed
earlier, Mrug said.
Still, she and Biro both
said it's important for parents to monitor their kids as they grow older –
knowing where they are and who they are with – and they may need to start
earlier with daughters who mature sooner.
Rules and boundaries
In this study, the
importance of girls' friends was apparent. Regardless of when they started
puberty, girls with a best friend who behaved badly – talking back to adults,
lying and cheating, for example – tended to have more problem behaviour
And girls who matured early
seemed to be particularly influenced by that friend, the researchers found.
But while keeping tabs on
your child's friends is important, Mrug said, kids also need to feel they can
talk to their parents.
They are more likely to
tell you about their lives, she said, "if there is the foundation of a
close, supportive relationship and a history of setting rules and
The American Academy of Paediatrics
has more on development during puberty.