The arrival of puberty often surprises parents and children but it's especially shocking when it happens to 2nd and 3rd graders. Breast development—the first stage of puberty—normally begins in girls around 10 years of age but a new study published in the journal Pediatrics (August 2010), indicates that being overweight, obese, or exposed to certain chemicals may be affecting development.

Researchers at the Cincinnati Children's Hospital Medical Center studied 1,239 girls from New York, San Francisco, and Cincinnati. They found that while a larger proportion of all 7-and 8-year-old girls have breast development now than in previous generations, the increase was especially pronounced in Caucasians, where the rates of early breast development have doubled over the past two decades. By contrast, the percentage of African American girls showing signs of early puberty remained constant during the same period.

Possible Causes

Scientists don't have a definitive explanation for this change but believe obesity plays a role. Girls today are heavier than ever before and that excess weight may be causing the spike in hormones that trigger puberty. (Most evidence showed no change in breast development for white girls of normal weight.)

Researchers also suspect that exposure to chemicals in consumer goods and certain foods may play a role. Bisphenol A, or BPA, is a compound commonly found in plastics. Although it has been shown to mimic estrogen in animals, studies in humans are limited. In the meantime, blood and urine samples have been collected from the girls who will be followed over the next five years. In an effort to identify markers that indicate early puberty, the samples will be tested for environmental chemicals.

Regardless of why development starts, breast budding may be accompanied by other signs of early puberty including:

  • Body odor
  • Pubic hair
  • Skin breakouts/acne
  • Underarm hair

Growing Up Too Fast

Dealing with the unexpected physical changes at a young age is only part of the equation. Once puberty sets in, growth slows prematurely and girls may not reach their expected height. Experts also believe there is a link between early menstruation and breast cancer, though this particular study did not include data on the beginning of menstruation. Socially, there are also concerns. Looking different than your peers—and lacking the emotional maturity and experience to deal with it-&mdashan damage self-esteem.

What You Can Do for Your Daughter

Until the medical community understands exactly why some girls experience puberty early, ensure that your daughter eats a balanced diet, engages in regular exercise, and maintains a healthy weight. Make reasonable efforts to avoid unnecessary exposure to chemicals in food and the environment that may be linked to early puberty.

If you notice signs that your daughter's body is starting to develop early, discuss your concerns with your pediatrician. Hormone levels can be checked with blood or urine tests. In some cases, diagnostic tests and imaging may be performed to rule out tumors, thyroid problems, and other health issues that can cause irregular hormone levels.

If necessary, a pediatric endocrinologist can prescribe medication to block the hormones that set puberty in motion and even reverse changes already underway. With medication, it is possible to hold off Mother Nature, at least for a little while.


Kids Health/From Nemours Foundation