Follicle Stimulating Hormone (FSH) Test

Written by Joanna Goldberg and Lydia Krause | Published on July 9, 2012
Medically Reviewed by George Krucik, MD

What Is a Follicle Stimulating Hormone Level Test?

The follicle stimulating hormone (FSH) level test measures the level of FSH found within human serum. FSH is responsible for promoting and sustaining ovarian follicular growth in females and spermatogenesis in males. Your doctor will order an FSH level test to find the underlying cause of symptoms affecting the reproductive system.

What Is FSH?

FSH is secreted from the anterior pituitary gland. It functions in the regulation of the human reproductive system. The hormone is responsible for regulating the production of estrogen and progesterone within the ovaries. FSH, along with estrogen and inhibin (produced in the ovaries), are crucial for regulating a women’s menstrual cycle.

Men require FSH for proper development of the gonads and sperm production. Other hormones that work in tandem with FSH in the reproductive system are luteinizing hormone (LH), human chorionic gonadotropin (hCG), and thyroid stimulating hormone (TSH).

The Purpose of the FSH Level Test

An FSH level test uses human serum taken from a blood sample to measure the body’s level of FSH.

In women, the most common reasons for an FSH level test include:

  • assessing infertility problems 
  • assessing irregular menstrual cycles  
  • diagnosing disorders of the pituitary gland or diseases involving the ovaries

In men, an FSH level test may be done to:

  • evaluate a man’s low sperm count
  • assess hypogonadism or gonadal failure
  • assess testicular dysfunction

In children, an FSH level test might be used to determine if a child is experiencing precocious puberty (early puberty) or delayed puberty (sexual features or organs do not develop when they should).

What Should My Doctor Know Before I Take the Test?

Talk to your doctor about any prescription or nonprescription medications, dietary supplements, and vitamins you are currently taking before any medical test is performed. Inform your doctor if you are using any type of contraceptive (Nuvaring, the pill, patch, etc.) because this may play a role in your test results. Discuss existing medical disorders such as uncontrolled thyroid disease, sex-dependent hormone tumors, ovarian cysts, and unusual vaginal bleeding with your doctor. They may be associated with FSH levels.

What Happens During the Test?

The test for the FSH level is very simple. Upon arriving at the doctor’s office, you will meet with a phlebotomist. He or she will tie a tourniquet above the site from which the blood will be taken. He or she will clean and sterilize the injection site with antiseptic and will insert a needle directly into your vein.

Most people feel a few moments of sharp pain at the initial poke, but this will quickly fade as the blood is drawn. The needle will be removed within a few minutes and you will be asked to apply pressure to the site with a cotton ball or small cloth. A bandage will be placed on the site and you will be free to leave.

Risks Associated with the Test

With any procedure, a small amount of risk involved. Slight risks include:

  • vasovagal syncope (fainting at the sight of blood)
  • dizziness or vertigo
  • infection
  • bruising (hematoma)
  • pain
  • redness at needle site

Interpreting Your Results

FSH levels vary based on gender, age, and where a female is in her monthly cycle. Each lab has a slightly different reference range. Discuss your results with your doctor.

 

Group

Range (IU/L)

Males

 

prepubertal

< 3

adult

1.3 to 19.3

Females

 

prepubertal

< 3

follicular

3.8 to 8.8

midcycle

4.5 to 22.5

luteal

1.8-5.1

postmenopause

16.7 to 113.6

High FSH Levels

High FSH levels in women may indicate a loss of ovarian function before age 40 (also called ovarian failure) and menopause.

High FSH values in men may indicate:

High values in children may mean that puberty is about to start.

Low FSH Levels

Low FSH values may indicate that:

  • a woman is not producing eggs
  • a man is not producing sperm
  • the hypothalamusorpituitary gland (hormone control centers in the brain) is not functioning properly
  • a tumor is interfering with the brain’s ability to control FSH production.

Stress and being severely underweight can affect FSH values.

An increase in FSH in women may indicate a reduction in the production of good quality eggs and embryos for fertilization. A common reason for this is a woman’s age. As women get older, fertility starts to decline and fewer eggs mature in a woman’s ovaries. The quality of those that remain is lower than during earlier years.

In conjunction with other tests for luteinizing hormone (LH), estradiol, and progesterone levels, the FSH level test helps determine a woman’s ovarian reserve. The term ovarian reserve refers to a woman’s age-related fertility potential. A high FSH level means a woman’s chances for pregnancy may be lower than expected for her age. However, it does not mean she has no chance of conceiving. She may have more difficulty conceiving and may require infertility treatment.

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Article Sources:

  • Collaborative Laboratory Services. Follicle Stimulating Hormone (FSH) in Serum: Lab Protocol. NHANES, 2001-2002.
  • Micromedex (2011, November 1). Follicle Stimulating Hormone and Luteinizing Hormone (Intramuscular Route, Subcutaneous Route). Mayo Clinic. Retrieved May 24, 2012, from http://www.mayoclinic.com/health/drug-information/DR600403
  • Mogensen, S. S., Aksglaede, L., Mouritsen, A., Sorensen, K., Katherine, M. M., Gideon, P., & Juul, A. (2011). Diagnostic Work-Up of 449 Consecutive Girls Who Were Referred to be Evaluated for Precocious Puberty. Clinical Endocrinology Metab, 96(5), 1393-1401.
  • Telikicherla, D., Ambekar, A., Palapetta, S. M., Raju, R., Sharma, J., Prasad, T. K., . . . Pandey, A. (2011). A comprehensive curated resource for follicle stimulating hormone signaling. BMC Research Notes, 4, 408.
  • Thum, M. Y., Kalu, E., & Abdalla, H. (2009). Elevated Basal FSH and embryo quality: lessons from extendedculture embryos. Journal of Assisted Reproductive Genetics, 26, 313-318.
  • White Sands Research Center. Follicle Stimulating Hormone (FSH) in Serum: Lab Protocol. NHANES, 2001-2002.

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