FSH Levels and Your Fertility

The Biomarker Handbook is a curated series that seeks to provide readers with insights on each biomarker we cover in our blood test packages and its relation to our body.


Having a balanced level of hormones is vital for proper reproductive capability. Follicle-stimulating hormone (FSH) is naturally found in both men and women. It plays a critical role in a woman’s ability to get pregnant.

Importance of FSH

FSH plays a crucial part in reproductive health. The pituitary gland, which is located on the underside of the brain, discharges this hormone.

In females, FSH controls the menstrual cycle and stimulates ovulation, which is the release of eggs from the ovaries. In males, FSH supports the development of sperm. Without the release of FSH, a woman’s reproductive cycle will be discontinued, as an egg will not be released from her ovaries.

Why an FSH test should be done

An FSH test measures the level of FSH in the blood. It can be used to assess a woman’s reproductive capability to determine if she has reached menopause.

Your doctor may also advise taking an FSH test to:

  • Evaluate inconsistent menstrual cycles, including periods which are irregular or absent (amenorrhea)
  • Gauge the onset of puberty in young adults, whether early or late
  • Diagnose pituitary gland disorders, including pituitary tumour

An FSH test on its own is rarely used to diagnose a disease. In fact, your doctor may recommend you to take additional hormone blood tests before coming to a final decision about the prevalent condition.

Understanding your results

Normal FSH values

The normal levels of FSH in a woman’s blood vary widely depending on her menstrual cycle. It usually peaks before ovulation. Men, on the other hand, have relatively constant amounts of FSH.

High FSH values

When the results come back with raised FSH levels, you may wonder what this implies about your fertility.

High FSH values in women may indicate:

  • Failure of the ovaries or loss of function
  • Occurrence of menopause
  • Polycystic ovarian syndrome (PCOS), a hormonal disorder causing: an irregular pattern of menstrual periods (sparse or prolonged), cysts in the ovaries, or a surplus of androgen (male hormone) levels
  • A reduced ability to produce good quality eggs for fertilisation. This may be due to ageing, as fertility declines with age. Therefore, high FSH values in women may point to low ovarian reserves, which translate to lower than expected chances of becoming pregnant.

High FSH values in men may suggest:

  • Klinefelter syndrome, a genetic condition affecting males, which is caused by an extra copy of the X chromosome
  • Absent or non-functional testicles.
  • Damaged testicles, which may be caused by alcohol dependence, or medical treatment such as X-rays and chemotherapy.

High FSH values in children may signify the onset of puberty.

Low FSH values

Conversely, low FSH values may indicate the following:

  • A lack of sperm or eggs being produced
  • Severe stress, starvation or being extremely underweight
  • Subpar functioning of the hypothalamus and the pituitary gland, which operate as the brain’s “command centre”
  • The presence of tumours in the brain, which may interfere with the brain’s ability to control the amount of FSH produced.

What can affect FSH test?

The outcome of FSH test is potentially affected by reproductive hormones (found in birth control pills) or the concurrent use of certain medications. Lifestyle choices such as heavy tobacco smoking and age play a role as well.

Striking a balance

FSH plays a vital role in the reproductive system for men and women alike. Getting pregnant requires a delicate hormone balance. Any disturbance to the balance of hormones can have an impact on the menstrual cycle and influence your chances of fertility.


If you want to find out more about FSH and how to maintain healthy levels, take a look at our lifestyle article here!

Interested in other biomarkers? Check out the rest of The Biomarker Handbook.

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