FSH: if you are a woman and an adult, it is very likely that these three letters have already appeared in some test request from your gynecologist. But what is FSH, what is the test for, and what do its results mean?

What is FSH?

FSH is the acronym for follicle-stimulating hormone, a substance produced in the pituitary gland (a gland located at the base of the brain) and linked to fertility. Its function is to stimulate the ovary to produce another hormone, called estradiol, and thereby mature the eggs - which start as primordial follicles until they become mature.

Men also produce FSH. In them, the hormone's function is to stimulate the production of sperm.

What is the exam for?

Through the dosage of this hormone in the blood, it is possible to evaluate a series of problems related to reproductive health: precocious or delayed puberty, inadequate egg production, causes of delayed menstruation, among others.

In men, the dosage is an indicator to evaluate sexual impotence, low sperm counts, and whether the testicles are functioning properly.

How to know if the FSH is normal?

There is a table of reference values for FSH, which vary according to age, gender, and, in the case of women of childbearing age, the phase of the cycle in which the test is done.

Thus, for adult men, the values considered to be within the standard range are between 1.4 and 13.8 mIU/mL.

But for women, the table changes:

• Follicular Phase: 3.4 to 21.6 mUI/mL.
• Ovulatory: 5.0 - 20.8 mUI/mL.
• Luteal phase: 1.1 - 14.0 mUI/mL.
• Menopause: 23.0 - 150.5 mUI/mL.

"During menopause, the values get high because the brain understands that the ovary is not working, so it increases the production of FSH to try to make it work again," explains gynecologist Mariana Rosário, from São Paulo.

On the other hand, if it is at low levels, the cause is usually the use of contraceptives: "This is because, in this case, there is an external stimulus in the body and the brain understands that it doesn't need to generate so much hormone for egg production. This demand is already coming from outside," explains the doctor.

"So these are the main causes of changes in FSH level in women: early ovarian failure, menopause, and contraceptive use," summarizes the gynecologist.

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