Leuprolide Stimulation Test

What is a leuprolide stimulation test?

A leuprolide stimulation test (sometimes called a GnRH stimulation test) helps show if your child has started puberty. Leuprolide is a medicine that acts like a natural hormone in the body called gonadotropin-releasing hormone (GnRH). It temporarily stimulates the pituitary gland to release hormones that control puberty. During the test, your child receives leuprolide, and blood samples are collected to see how their body responds. 

During puberty, your child’s body undergoes physical and hormonal changes. Puberty starts when your child’s hypothalamus and pituitary glands send signals to their reproductive organs (ovaries in females and testes in males) to produce and release sex hormones. This causes physical changes in the body, such as: 

• Growth of pubic and underarm hair 
• Growth of the penis and testes, facial hair, and a deeper voice in males 
• Breast development and menstrual periods in females 

Puberty usually begins between the ages of 8 and 13 in girls and 9 and 14 in boys. If your child starts puberty before age 8 in girls or age 9 in boys, they may have a type of puberty problem due to issues with their hormones, known as precocious puberty (early puberty).  

Puberty problems can be caused by some cancer treatments, such as radiation or surgery to the head or brain. They can also result from hormone problems in the hypothalamus, pituitary gland, testes, or ovaries.   

How to prepare for the stimulation test

Your care team will give you information on how to prepare for the test and what to expect. Always follow their instructions. In most cases: 

• Your child can eat and drink as usual before the test. 
•  You can give your child their usual medicines unless your care team tells you otherwise. 
• Dress your child in comfortable clothes.  
• Bring activities that will keep them busy during the test, such as books, games, or tablets. 

What to expect during the test

Your care team will explain what to expect. In general: 

• You can stay with your child during the test.  
• Before the test, your care team will place an IV in your child’s arm to use for blood samples. They may numb the skin before placing the IV. 
• The nurse will give your child an injection (shot) of the medicine, leuprolide, under the skin in the upper arm. 
• During the test, the care team will draw blood samples from the IV at scheduled times (usually 30 and 60 minutes). 
• A nurse will monitor your child during the test and remove the IV when the test is done. 

The test usually takes about 3–4 hours. In some cases, you may need to return to the clinic the next morning for more blood tests. 

Possible side effects of the stimulation test

The test is generally safe, and any side effects are usually mild and improve soon after the test.  

Possible side effects include: 

• Feeling dizzy or lightheaded 
• Pain or discomfort from the needle stick  
• Mild bleeding or bruising at the IV site  
• Temporary flushing (redness of the skin) 
• Feeling warm suddenly (hot flashes) 

After the stimulation test

Your child can return to normal activities after the test.   

Blood samples are sent to the lab for testing. Your care team will share the test results with you and tell you what they mean. 

What test results mean 

This test measures how your child’s body responds to hormones that control puberty. Your child’s results may show one of the following:  

• Puberty has not started: Hormone levels stay low after the medicine. This usually means puberty has not started. 
• Puberty has started: Hormone levels increase after the medicine as expected. This usually means puberty has started. 
• Early puberty: Hormone levels rise in a pattern that may suggest precocious puberty. 

Your care team will review the results and discuss other tests or treatments that are needed.

Questions to ask your care team

• Why does my child need a leuprolide stimulation test? 
• How should my child prepare for the test? 
• Can my child take their usual medicines before the test? 
• How long will the leuprolide stimulation test take? 
• What happens during the test? 
• Are there any risks or side effects from the test? 
• When can I expect the test results, and what do the results mean? 
• Will my child need other tests? 

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