FSH Hormone

23 May, 2022

Escrito por el equipo médico fivmadrid

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The follicle-stimulating hormone involved in the control of the menstrual cycle.

¿Qué es la FSH?

La FSH u hormona folículo estimulante, es una hormona de la familia de las gonadotropinas. Las hormonas gonadotropinas, LH (hormona luteinizante o lutropina) y la FSH (hormona folículo estimulante o folitropina), se fabrican en una zona del encéfalo denominado: eje hipotálamo-hipofisiario.

What is FSH?

FSH, or follicle stimulating hormone, is a hormone of the gonadotropin family. The gonadotropin hormones, LH (luteinising hormone) and FSH (follicle-stimulating hormone), are made in an area of the brain called the hypothalamic-pituitary axis.

Both hormones interact in both the male and female sexes. In women, they control the menstrual and ovarian cycle, while in men they act in the testicles to produce testosterone and participate in spermatogenesis. Therefore, we can say that they are not exclusively women’s hormones, but that they perform different functions in men and women.

¿Para qué sirve la FSH?

La FSH, como su nombre indica, estimula el crecimiento folicular y la selección del folículo dominante. Este será el destinado a romperse y liberar el óvulo maduro que de ser fecundado por un espermatozoide dará lugar a un embarazo.

What is FSH used for?

FSH, as its name suggests, stimulates follicular growth and the selection of the dominant follicle. This is the one destined to rupture and release the mature egg which, if fertilized by a sperm, will result in pregnancy.

However, a good understanding of the function of FSH requires a review of the menstrual cycle.

The menstrual cycle lasts between 24 and 38 days and begins with menstruation, which lasts about 7 days. After menstrual bleeding is over, the follicular phase follows, which lasts about 14 days. During this phase, FSH recruits several follicles, of which only one is chosen so that, once it has completed its growth and maturation phase, it ruptures and releases the egg.

Al mismo tiempo que los folículos crecen, las células granulosas foliculares producen estrógenos; que van aumentando progresivamente. Al final de la fase folicular, los estrógenos circulantes son tan elevados que inducen al eje hipotálamo-hipofisario a la liberación de la hormona LH (luteinizante); la cual será la encargada de que el folículo dominante se rompa y libere el ovulo maduro para ser fecundado. El ovulo viajara por las trompas de Falopio para encontrarse con los espermatozoides y ser fecundado.

As the follicles grow, the follicular granulosa cells produce estrogen, which increases progressively. At the end of the follicular phase, the circulating estrogens are so high that they induce the hypothalamic-pituitary axis to release the hormone LH (luteinizing hormone), which will be responsible for the dominant follicle rupturing and releasing the mature ovum for fertilization. The egg will travel through the fallopian tubes to meet the sperm and be fertilized.

If it is fertilized, the pre-embryo will implant in the uterus and may sometimes produce implantation bleeding. On the other hand, if fertilization does not occur, menstruation will appear after 14 days, starting a new menstrual cycle.

What is FSH used for in assisted reproduction treatments?

In assisted reproduction treatments FSH is used to stimulate the recruitment of ovarian follicles and produce more mature eggs than normal, thus increasing the chances of getting pregnant.

Basal blood levels of FSH hormone, together with AMH levels and ultrasound are important because they indicate what the follicular reserve may be and the response to assisted reproduction treatments.

The normal values of FSH for pregnancy are between 3-9 mIU/ml, of the hormone fsh, these normal values are considered acceptable for good fertility. High FSH values can mean low ovarian reserve, menopause or Turner syndrome among other problems. Low levels, on the other hand, may be linked to underweight, anorexia and hypogonadism.

What does high FSH mean?

High FSH may be an indicator of needing assisted reproductive treatment to achieve the desired pregnancy.

Before starting any assisted reproduction treatment, circulating blood values of FSH should be assessed.


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