The project aims to establish the normal LH and FSH response to a standardized GnRH dose in healthy girls below 6 years of age, and compares the normal GnRH response to the GnRH response in girls with early puberty development.

The novel data may help to determine whether the girl is in early puberty or not.

Healthy girls under 6 years of age attending routine examinations including an i.v. line for other causes are included in this study. Our examinations also include bone age determination, Tanner stage determination, and anthropometric measures (height and weight). 10 healthy girls in each of the following age groups: 7-12 months, 12-24 months, 24-36 months, 36-48 months, 48-60 months and 60-72 months are included.

Please refer to the brief summary which covers the study aim, methods and outcome measures.

Inclusion Criteria:

• Endocrinologically healthy girls in the age from 7 months to 6 years
• Obtained oral and written informed consent from participants parents

Exclusion Criteria:

• Anamnestic, clinical or laboratory findings that indicate that the subject is suffering from other diseases (eg poorly controlled asthma) or is in a condition which might affect the subject's ability to complete the study or which is likely to affect the parameters under investigation.
• Current medical treatment apart from prophylactic antibiotics or weak analgesics.
• GFR <50 ml/min/1,73m2 or if absence of previous GFR study: serum creatinine above normal upper age-specific normal range.
• Clinical signs of precocious puberty