Basal luteinizing hormone/follicle stimulating hormone ratio in diagnosis of central precocious puberty.

BACKGROUND

Precocious puberty is characterized by breast development in girls prior to 8 years old and may have acne, adult odor, growth spurt and menstruation. Conventionally, gonadotropin releasing hormone (GnRH) stimulation test is a gold standard for diagnosis of central precocious puberty but it is a time-comsuming procedure that is not practical on an out patient basis.

OBJECTIVE

To evaluate the basal luteinizing hormone (LH)/follicle stimulating hormone (FSH) ratio in diagnosis of central precocious puberty in order to save time and cost.

SUBJECTS AND METHOD

The GnRH stimulation tests were performed on 51 girls with breast development before 8 years old. The 51 girls were divided into 2 groups, 24 girls with central precocious puberty (CPP) and 27 girls with premature thelarche (PT), and the clinical data and GnRH stimulation tests data were compared between the 2 groups. The authors also compared the clinical data and GnRH stimulation tests data between 13 girls with PT and 12 girls with thelarche variants (TV) who developed puberty approximately 1 year later as confirmed by GnRH stimulation test.

RESULTS

Girls with CPP had a large bone age and chronological age ratio and advancement of breast staging. Girls with TV had a greater level of basal luteinizing hormone (LH), peak LH and 120 min estradiol than girls with PT. Basal luteinizing hormone and follicle stimulating hormone (FSH) ratio greater than 0.2 can be used to diagnose CPP with 75 per cent sensitivity, 85 per cent specificity, 82 per cent positive predictive value (PPV) and 82 per cent negative predictive value (NPV).

CONCLUSION

Girls with CPP have a basal LH/FSH ratio greater than 0.2 and this can be used as a cut-off point for the diagnosis CPP.