Urinary gonadotropin levels aid precocious puberty diagnosis

Urinary gonadotropin levels increased shortly before the onset of puberty among girls and boys, according to researchers in Denmark. In particular, girls with precocious puberty demonstrated higher urinary luteinizing hormone levels that normalized after treatment with gonadotropin-releasing hormone agonists.

Researchers wrote that the findings may aid in the diagnosis and management of disordered puberty in children.

“Due to the lack of significant GnRH [gonadotropin-releasing hormone (GnRH)] release in childhood, levels of pituitary gonadotropins — follicle-stimulating hormone (FSH) and luteinizing hormone (LH) — remain very low before the onset of puberty,” Nanna Kolby, of the department of growth and reproduction at Rigshospitalet, Copenhagen, and colleagues wrote. “The GnRH stimulation test, considered the gold standard for diagnosing pubertal disorders, is a procedure that requires hospitalization and only few normative data for GnRH-stimulated values exist. … As an alternative, noninvasive method for evaluating the function of the [hypothalamic-pituitary-gonadal hormone axis], measurement of the gonadotropin concentrations in first morning voided urine has been proposed.”

The researchers performed a cross-sectional study of healthy children who had participated in the COPENHAGEN Puberty Study, as well as girls suspected of having central precocious puberty (n = 843 from COPENHAGEN study; n = 25 girls evaluated for precocious puberty). The main outcomes were staging of precocious puberty, as well as urinary and serum gonadotropin levels.

Urinary gonadotropin levels rose as the children aged, the researchers reported, and were detectable in first morning voided urine before children began showing signs of puberty. LH in first morning voided urine was strongly correlated with both basal (r = 0.871; P < .001) and GnRH-stimulated serum LH (r = 0.82; P < .001).

Urinary LH was better for differentiating children’s pubertal stage than FSH, Kolby and colleagues wrote. A cutoff standard-deviation score of 2 IU/L for urinary LH produced a sensitivity of 75% in predicting a positive GnRH stimulation test and a specificity of 92%, the researchers reported. After 3 months of GnRH treatment, LH concentrations fell below two standard-deviation increases.

“Our data suggest that [first morning voided] urinary concentrations of LH can be used as a diagnostic marker in girls suspected of [central precocious puberty],” the researchers wrote. “In addition, we suggest measurement of unadjusted [first morning voided] urinary concentrations of LH as a method for monitoring treatment with GnRH agonists in girls with [central precocious puberty].” – by Andy Polhamus

Disclosures: The authors report no relevant financial disclosures.