Folliculotropic hormone (FSH) testing - what is it and how does it work?
When guiding a patient through the diagnostic process of infertility, pituitary disease or menstrual and ovulatory disorders, FSH levels are most often ordered. Its low or elevated levels can affect fertility. Such a test is also performed in children in cases of impaired puberty.
FSH testing - what is it?
The FSH test is a test of the concentration of the gonadotropin FSH, or folliculotropin, produced by the pituitary gland. The test is also used to diagnose pubertal and menstrual disorders, as well as infertility and impotence.
The mechanism of action of the folliculotropic hormone FSH is sex-dependent. In women, the hormone regulates changes in the endometrium during one phase of the menstrual cycle and is involved in the selection and maintenance of the dominant follicle in the ovary. A woman's FSH concentration depends on the day of her cycle and her age. Adequate hormone concentrations are indicative of the normal function of the hypothalamic-pituitary-gonadal axis. If it is disturbed, it can be one of many causes of fertility disorders.
In men, the hormone FSH is responsible for the maintenance and stimulation of spermatogenesis. The secretion of this hormone is regulated by oestradiol and testosterone. These interact with the hypothalamus, which then triggers a response to the pituitary with the hormone gonadoliberin (GnRH).
For what purpose is the FSH test performed?
In women
The hormone FSH stimulates the ovaries to produce oestrogens (so that the ovarian follicles mature better), influences the menstrual cycle and stimulates ovulation. Testing the FSH concentration in the blood in women is one of the tests performed for suspicion and evaluation:
-
ovarian reserve,
-
the presence of polycystic ovaries,
-
causes of menstrual disorders such as irregular periods or intermenstrual bleeding.
In men
The hormone FSH stimulates the production of sperm in the testes and stimulates the production of proteins that bind sex hormones. FSH testing in men is performed when FSH levels are suspected and assessed:
-
low levels of sperm in the semen,
-
testicular function,
-
testosterone levels,
-
the quality of the sperm produced.
The hormone FSH influences the maintenance of an appropriate pubertal process. Too high or low concentrations can contribute to premature or too late puberty. FSH testing in children allows the assessment of their pubertal cycle and the changes occurring in it.
How is the FSH hormone controlled?
The production and emission of the hormone FSH are regulated by a number of hormones released from the ovaries and testes.
This system works along the hypothalamic-pituitary-gonadal axis. The hypothalamus circulates gonadotropin-releasing hormone, which then binds to the receptors of the anterior lobe of the pituitary gland. This stimulates the synthesis and release of folliculotropic hormone, which is carried into the bloodstream. It is there that it binds to receptors in the ovaries and testes. Consequently, FSH hormone and luteinising hormone can, using the system in question, control the function of the female and male genital organs.
When is the best time to perform the hormone determination?
FSH hormone testing should take place in the morning. This is related to the diurnal rhythm of hormone secretion by the pituitary gland.
In women and in young menstruating girls, the test is performed between days 2 and 5 of the menstrual cycle (i.e. in the early follicular phase) - unless otherwise advised by the doctor.
In children (non-menstruating boys and girls) and in men The specific day of the examination does not matter. However, it is important to go to the clinic first thing in the morning.
Folliculotropic hormone testing in women is usually performed when fertility problems, menstrual disorders and puberty are noticed. FSH is one of the hormones that regulate a woman's menstrual cycle. In a worrying situation, it is advisable to see a specialist.
In men, FSH hormone testing is performed, among other things, in the event of low sperm count in semen, in the diagnosis of infertility or even in the case of suspected pituitary disease.
Normal FSH levels - performance standards
Below are the norms for FSH hormone levels according to a woman's age, sex and menstrual cycle.
Norm of FSH in a woman during the phases of the menstrual cycle:
-
Phase 1 of the cycle (menstruation) - 3-12 IU/I;
-
Cycle phase 2 (follicular, follicular phase) - <12 IU/I;
-
Cycle phase 3 (ovulatory phase) - 20-90 IU/I;
-
Cycle phase 4 (luteal phase) - <10 IU/I.
FSH norm in a woman:
-
during pregnancy - <0.3 IU/I,
-
during menopause - 40-250 IU/I,
-
After the menopause - the FSH hormone increases.
FSH norm in a man:
-
Before puberty - <0.4 IU/I;
-
during puberty - 1-9.2 IU/I.
-
after puberty - from 1.4 to 12 IU/I.
FSH norm in children:
-
From 1 - 5 years of age - <0.4 IU/I;
-
girls before first menstruation - 1-12 IU/I;
Elevated FSH
High FSH levels in women can mean reduced ovarian reserve, which is also associated with fewer oocytes and follicles. This can mean low chances of getting pregnant.
Elevated FSH and LH in women with concomitant low serum oestradiol levels is typical of the menopausal period.
In contrast, the same case in a woman under 40 years of age may be indicative of:
-
Premature ovarian failure (POF/POI),
-
extinction of ovarian function as a result of, for example, disease or chemo- or radiotherapy,
-
ovarian tumour,
-
polycystic ovary syndrome (PCOS, is one of the main causes of infertility in women),
-
peri-menopausal period or the onset of menopause,
-
inadequate hormone therapy.
In men, elevated FSH can mean:
-
testicular insufficiency,
-
damage to the testes, e.g. through infectious agents causing impaired sperm production, alcoholism, chemotherapy, radiotherapy,
-
Primary hypogonadism, such as in Klinefelter's syndrome,
-
advanced age (otherwise known as male menopause),
-
inadequate hormone therapy,
-
pituitary tumours,
-
pituitary or hypothalamic disorders.
In contrast, high levels of FSH and LH in children may indicate that puberty is about to begin or has already begun. On the other hand, if this happens before the age of nine in a girl or before the age of 10 in a boy, it may indicate premature puberty.
Low levels of the hormone
Low FSH levels can result from a number of abnormalities in the body. In women, as in men, one of the most common is severe and chronic stress and medications taken that interfere with the functioning of sex hormones. What else?
Decreased FSH hormone in women can occur with:
-
abnormal functioning of the pituitary or hypothalamus,
-
endocrine dysfunction of the ovaries,
-
hypothalamic problems,
-
severe underweight (e.g. through anorexia or severe malnutrition),
-
pregnancy,
-
hyperprolactinaemia.
In contrast, low FSH levels in men
indicate a disorder of the pituitary or hypothalamus - they do not produce adequate amounts of all or some sex hormones.
Abnormal FSH levels in children
Can be a sign of delayed sexual maturation. This can be caused by:
-
Turner's syndrome in girls,
-
infection,
-
deficiency of certain hormones,
-
eating disorder,
-
an ovarian or testicular disorder,
-
Klinefelter syndrome in boys.
In children, low FSH levels can manifest as noticeable physical changes.
How to prepare for the FSH test?
For women, the FSH test should be taken between days 1 and 5 of the menstrual cycle (i.e. in the follicular phase) - unless your doctor advises otherwise. During the consultation with your doctor before the FSH test, you should tell him or her what medicines you are currently taking. Your doctor, after careful consideration, may recommend that you stop taking them up to four weeks before the test. Otherwise, they may affect the result. The test results may also be affected by the presence of a radioactive tracer, e.g. after a thyroid or bone scan. Your doctor should also be informed if you are undergoing such diagnostics.
Before the examination, it is recommended not to drink alcohol, smoke or engage in intense physical activity. It is also advisable to avoid drinking large amounts of tea or coffee and to refrain from eating for a maximum of 12 hours. On the day of the FSH test, on the other hand, you should remember to drink two glasses of water (without sugar or other flavours). You should also arrive on an empty stomach and be well rested. A little while before you can sit at rest for about 10, 15 minutes in a sitting position.
What is the course of the study?
The FSH test involves a standard blood draw in the clinic from the elbow vein using a needle by an authorised person. Once the needle is inserted, a small amount of blood will be drawn into a tube or vial. You may feel a slight prick during the test - especially when the needle is withdrawn or inserted into the ulnar vein. The test usually takes a maximum of five minutes.
What to expect from the test performed?
After the examination, there may be a small haematoma or damage to a vessel at the injection site - nothing more. Such an examination is completely safe and does not interfere with the patient's health. The result of the FSH test is measured in what are known as 'milli-units per millimetre', or mlU/ML for short. You usually wait one or two days for the results. The exact date will be given by the attending doctor.
The result of the test can tell you the level of the FSH hormone in your body. If it is elevated, which means among other things a lower ovarian reserve and a low possibility of pregnancy, the doctor will determine the appropriate treatment.
However, it is important to note that the doctor may need additional tests for other sex hormones, as high or low FSH alone is not enough for the doctor to make a definitive diagnosis. Your doctor may order additional tests:
-
the luteinising hormone LH,
-
oestrogen,
-
testosterone.
If your FSH levels are normal, but there is another problem that makes it difficult to get pregnant (e.g. low sperm count, poor egg or embryo quality) your doctor will suggest another solution to speed up the time to pregnancy.
Which hormone levels should be measured in parallel with FSH?
FSH should be tested in parallel with oestradiol, as it is subject to negative feedback from oestradiol. This means that FSH secreted by the pituitary influences the production of oestradiol by the ovaries, whose higher levels feedback into a decrease in FSH secretion by the pituitary (the effect inhibits the cause).
It may be that a low FSH value is the result of a high concentration of oestradiol, produced by a functional ovarian cyst.
FSH and hormonal stimulation
FSH is an indirect marker of ovarian reserve and allows assessment of the response from the ovary to stimulation with exogenous FSH (folliculotropic hormone introduced externally in the form of a pharmacological agent).
Traditionally, a serum FSH value of more than 15 IU/L on day 2-3 of the cycle is considered a predictor of a poor response to stimulation and is the basis for excluding the patient from further hormonal stimulation - this can mean a lack of response to exogenous FSH, i.e. no follicle growth in the ovary.
Frequently asked questions
1. what fsh result is indicative of menopause?
Menopause in FSH tests manifests itself with a hormone level above 25 IU/I but, above all, with the absence of menstruation. However, this result can increase further.
2. How long do you have to wait for the test results?
There is usually a wait of one or two days for the FSH test result. However, detailed information can be obtained from the doctor performing the test.
3. what can FSH levels depend on?
Lowering FSH levels can be affected by hormonal drugs, contraceptives and corticosteroids. On the other hand, drugs such as cimetidine, ketoconazole (an antifungal drug), clomiphene (a drug for infertility and ovulatory disorders), glycosides, levodopa (a drug for Parkinson's disease), erythropoietin (a drug for haematological diseases and kidney failure) and nicotine can have an effect on an increase.
4 Does FSH have an impact on IVF?
Yes. The FSH level helps to assess the patient's chances of responding correctly during hormonal ovarian stimulation or the chances of obtaining sperm.
Substantive consultation:
Dr. Marcin Trzeciak - Specialist gynaecologist-obstetrician
Download free Invimed e-books
The e-books published by Invimed are free and freely available to the public. We dedicate them to people who are in the process of trying to have a baby - whether on their own or supported by infertility clinics. We are here for you.