Evaluation for early puberty: When, why, and how

A workup is indicated for a child with signs of puberty starting before the normal lower age limits to determine whether the developmental changes represent normal variation or a pathologic process.

In his session titled “Office evaluation of the child with early signs of puberty” on Saturday, October 22, Dennis Styne, MD, discussed current concepts on the timing of puberty and laboratory testing for suspected precocious puberty.

“Central gonadotropin dependent precocious puberty may be due to a genetic mutation or a congenital or acquired central nervous system disorder. It is important to be sure that any child with early puberty that appears to be driven by the hypothalamic-pituitary axis is not caused by a brain tumor,” said Styne, professor and Yocha Dehe Chair in Pediatric Endocrinology, University of California Davis School of Medicine, Sacramento.

According to older textbooks, the earliest normal age of puberty was reported at 8 years for girls and 9 years for boys. Based on more recent evidence, however, it is now generally accepted that puberty may occur normally at age 6 years in African American girls, age 7 in Caucasian girls, and age 9 in boys if there is no finding suggesting an associated pathological disorder.

However, further analyses of available data indicated that girls who went into puberty at these younger age guidelines had an increased body mass index (BMI). Therefore, a girl with a normal BMI may nonetheless have a disorder at these ages, Styne said.

Evidence also showed that boys who are overweight with a BMI in the 85th to 95th percentile for their age had earlier puberty whereas puberty occurred later in obese boys (ie, BMI >95th percentile).

“It appears that environmental changes that have led to the obesity epidemic are having a significant effect on the age of pubertal development. Although not conclusive, there is also some highly suggestive evidence that environmental endocrine disrupting chemicals are playing a role in the shift to earlier timing of puberty,” Styne noted.

Considering the information on timing of puberty, pediatricians should have a high index of suspicion and initiate evaluation with laboratory testing for girls who show breast or pubic hair development if they are Caucasian and aged younger than 7 years, or African American and aged younger than 6 years. Physicians should also consider such evaluation for girls who are not overweight or obese and aged younger than 8 years. The recommendation for boys is still to initiate an evaluation if they develop pubic hair or genital changes before age 9 years.

“Ruling out a brain tumor is important in any child with central gonadotropin dependent precocious puberty but even more important in boys because they have a higher risk for this etiology than girls,” Styne said.

Laboratory testing should evaluate levels of sex steroids (estradiol and testosterone, respectively) and gonadotrophins (luteinizing hormone and follicle stimulating hormone), and should be performed using specialized pediatric assays.

“In children being evaluated for precocious puberty, we are looking for levels of these hormones that are below the detection limits of the standard adult assays used in most laboratories,” Styne explained.

Ms Krader has 30 years’ experience as a medical writer. She has worked as both a hospital pharmacist and a clinical researcher/writer for the pharmaceutical industry, and is presently a freelance writer in Deerfield, Illinois. She has nothing to disclose in regard to affiliations with or financial interests in any organizations that may have an interest in any part of this article.