What is follicle-stimulating hormone?
The follicle-stimulating hormone is a hormone produced by the pituitary gland, a small gland located at the base of the brain. It is an essential hormone for the reproductive system in both males and females. It also plays a role in sexual development and functioning.
The functions of follicle-stimulating hormone are:
In females:
- Puberty: FSH plays a key role in initiating puberty around the age of 10 to 14 years. It stimulates the ovaries to develop follicles, which are small sacs that contain immature eggs. As follicles grow, they begin to produce estrogen, leading to the development of secondary sexual characteristics like breast development and the start of menstrual cycles.
- Menstrual Cycle: At the beginning of each cycle, FSH is released to stimulate multiple follicles in the ovaries. One of these follicles becomes dominant, matures, and prepares for ovulation (egg release). FSH works together with luteinizing hormone (LH) to regulate this process. The rise in estrogen from growing follicles also gives feedback to control FSH levels, ensuring only one egg is released per cycle.
- Fetal Development: During the second and third trimesters of pregnancy (weeks 13 to 26 and weeks 27 to birth, respectively), the fetus’s pituitary gland begins to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These hormone levels reach their peak around mid-pregnancy, coinciding with the maturation of the fetus’s first ovarian follicle in females or the seminiferous tubules (coiled structures within the testes) in males.
In males:
- Puberty: FSH and LH work together to stimulate the testes to start producing testosterone, the hormone responsible for the physical changes of puberty, such as body hair growth and voice deepening, as well as for sperm production.
What is follicle stimulating hormone test?
The follicle-stimulating hormone (FSH) test is used to measure the levels of FSH in the bloodstream. It is used to assess reproductive health and diagnose conditions related to fertility, menstrual irregularities, menopause, and certain disorders of the pituitary gland or ovaries/testes.
Why is the follicle-stimulating hormone test recommended?
A follicle-stimulating hormone test is recommended for the following reasons:
In women:
- Investigate infertility or difficulty conceiving.
- Diagnose menopause or perimenopause
- Assess pituitary gland function or disorders affecting hormone levels
- Evaluate delayed or early puberty in children
- Diagnose conditions like polycystic ovary syndrome (PCOS) or primary ovarian insufficiency.
In men:
- Evaluate testicular function
- Identify any issues related to sperm production
What is the procedure for the follicle-stimulating hormone test?
A healthcare professional takes a blood sample, usually from a vein in the arm. The blood is sent to a lab for FSH analysis. Sometimes the test is timed according to the menstrual cycle (often on day 3 of the cycle in women). This is because FSH levels are most stable and provide a clear baseline measure of ovarian function early in the cycle. This helps accurately assess ovarian reserve and reproductive health.
How to prepare for a follicle-stimulating hormone test?
Usually, no special preparation is needed for the follicle-stimulating hormone (FSH) test. However, for women, the timing of the test is important and is commonly done on day 3 of the menstrual cycle to ensure accurate results. It is important to inform your doctor about any medications or hormonal treatments you are taking, as these can affect hormone levels.
What are the normal results of a follicle-stimulating hormone test?
The normal results of the follicle-stimulating hormone test in females are:
- Follicular – 50-10.20 mIU/mL- During the early part of the cycle, FSH stimulates the growth of ovarian follicles. Levels are moderate to support this process.
- Mid Cycle Peak – 40-33.40 mIU/mL- Around ovulation, FSH temporarily rises to help mature the egg and trigger its release in coordination with a surge in LH.
- Luteal Phase – 50-9.10 mIU/mL- After ovulation, FSH drops because estrogen and progesterone provide negative feedback to the pituitary gland, suppressing FSH.
- Post Menopausal – 00-116.30 mIU/mL- After menopause, the ovaries stop responding to FSH, so there’s no estrogen to suppress its production. As a result, FSH levels rise significantly.
- Pregnant – <0.30 mIU/mL- During pregnancy, high levels of estrogen and progesterone suppress FSH production, so levels are very low.
What happens when follicle-stimulating hormone levels are high?
High follicle-stimulating hormone levels may indicate:
In women:
- Primary Ovarian Insufficiency (POI)
- Turner Syndrome
- Menopause or Perimenopause
- Polycystic Ovary Syndrome (PCOS)
- Pituitary tumor or damage
In men:
- Primary testicular failure or damage
What happens when the follicle-stimulating hormone levels are low?
Low follicle-stimulating hormone levels may indicate:
- Infertility issues
- Delays in sexual development
- Limited sperm production
What are the risks associated with the follicle-stimulating hormone test?
The follicle-stimulating hormone test involves minimal risk as it is a simple blood draw. Some people may experience slight pain or bruising at the site where the needle is inserted, and rarely, there may be a risk of infection or dizziness. Usually, no special preparation is needed before the test. However, in women, the timing of the test can be important and is often done on day 2 or 3 of the menstrual cycle.
FAQs
- What is FSH Test for?
The FSH test measures follicle-stimulating hormone level to assess reproductive health, fertility issues, menstrual irregularities, or hormonal imbalances.
- What happens if FSH is high in females?
High FSH in females may indicate reduced ovarian function, such as in menopause, premature ovarian failure, or poor egg reserve.
