title: The follicle-stimulating hormone (FSH) and luteinizing hormone (LH) response to a gonadotropin-releasing hormone analogue test in healthy prepubertal girls aged 10 months to 6 years.
abstract: OBJECTIVE
  Premature thelarche and precocious puberty are frequently diagnosed in girls even below 6 years of age and may be difficult to differentiate in the early stages. A GnRH test is often included in the diagnostic work-up, although interpretation of the GnRH test in girls below 6 years of age is challenging, as no reference interval exists for this age group. The objective is to determine the normal FSH and LH response to a GnRH test in healthy prepubertal girls below 6 years of age.
  
  
  METHODS
  A standardized GnRH test, baseline reproductive hormones, clinical evaluation and bone age were determined in all participants. Forty-eight healthy normal-weight girls aged 3.5 ± 0.2 years (range: 0.8-5.9 years) were included. Serum concentrations of LH and FSH were measured before and 30 min after the gonadorelin injection.
  
  
  RESULTS
  The 30-min LH responses (mean ± 2 s.d.) were 5.2 ± 4.0 and 2.9 ± 2.5 IU/L and the FSH responses were 23.3 ± 16.2 and 14.5 ± 10.3 IU/L in girls aged 0.8-3.0 years and 3.0-5.9 years respectively. This corresponds to upper cut-off limits for LH of 9.2 IU/L (<3 years) and 5.3 IU/L (3-6 years). The stimulated LH/FSH ratio was 0.23 ± 0.19 (range 0.06-0.43) and did not correlate with age.
  
  
  CONCLUSIONS
  We found that LH increases up to 9.2 IU/L during GnRH test in healthy normal-weight girls below 3 years of age and that the stimulated LH/FSH ratio did not exceed 0.43. Our findings have important implications for appropriate diagnosis of central precocious puberty in girls below 6 years of age.
authors.affiliation: Medical Research LaboratoryAarhus University, Aarhus, Denmark.|Department of PediatricsRanders Regional Hospital, Randers, Denmark.|Pediatrics and Adolescent MedicineAarhus University Hospital, Aarhus, Denmark.
authors.forename: Esben T
authors.initials: ET
authors.lastname: Vestergaard
authors.affiliation: Pediatrics and Adolescent MedicineAarhus University Hospital, Aarhus, Denmark.
authors.forename: Mia E
authors.initials: ME
authors.lastname: Schjørring
authors.affiliation: Pediatrics and Adolescent MedicineAarhus University Hospital, Aarhus, Denmark.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Kamperis
authors.affiliation: Department of RadiologyAarhus University Hospital, Skejby, Aarhus, Denmark.
authors.forename: Karin Kastberg
authors.initials: KK
authors.lastname: Petersen
authors.affiliation: Pediatrics and Adolescent MedicineAarhus University Hospital, Aarhus, Denmark.
authors.forename: Søren
authors.initials: S
authors.lastname: Rittig
authors.affiliation: Department of Growth and Reproduction and EDMaRCRigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Juul
authors.affiliation: Pediatrics and Adolescent MedicineAarhus University Hospital, Aarhus, Denmark.
authors.forename: Kurt
authors.initials: K
authors.lastname: Kristensen
authors.affiliation: Pediatrics and Adolescent MedicineAarhus University Hospital, Aarhus, Denmark.
authors.forename: Niels H
authors.initials: NH
authors.lastname: Birkebæk
mesh_terms: D000465:Algorithms; D001846:Bone Development; D002657:Child Development; D002675:Child, Preschool; D015331:Cohort Studies; D003718:Denmark; D003940:Diagnostic Techniques, Endocrine; D005260:Female; D043373:Follicle Stimulating Hormone, Human / Q000097:blood / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology; D006785:Hospitals, University; D006801:Humans; D007223:Infant; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D016011:Normal Distribution; D011629:Puberty, Precocious / Q000097:blood / Q000175:diagnosis / Q000378:metabolism; D012016:Reference Values; D012738:Sex Hormone-Binding Globulin
chemical_list: D043373:Follicle Stimulating Hormone, Human; D012738:Sex Hormone-Binding Globulin; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone