Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH)
Many times, when you open Baidu and type in “female hormones”: “What’s wrong with high FSH/LH?” “What’s wrong with low FSH and LH?” “What are the normal values of FSH and LH?” The questions keep jumping into your eyes, so let’s get to know you and me together today.
Where do FSH and LH come from?
If you analyze your intelligent brain, you will find that at the bottom of her central position, there is a light that lights up the night – the pituitary gland, which is the most important endocrine gland in the human body, divided into two parts: the anterior lobe and the posterior lobe, and FSH/LH is secreted by the anterior lobe, that is, the pituitary gonadotropin cells.
What is the origin of FSH and LH?
They are like parents who nurture the healthy growth and development of the follicles and promote their discharge from the ovaries.
FSH is necessary to stimulate follicular development, especially to promote the growth and development of antral follicles and sinus follicles (understood as small follicles); to promote the synthesis and secretion of estradiol; to select a good follicle for reproduction; and to induce the production of LH receptors in preparation for the expulsion of the dominant follicle.
LH, on the other hand, mainly stimulates androgen synthesis and provides substrate (i.e. basic substance) for estradiol; promotes further maturation and discharge of oocytes; and maintains luteal function.
What are the normal values of FSH and LH?
This may seem general, so let’s put it in another way: let’s talk about the changes in FSH and LH under physiological conditions. Specifically, their normal values are not fixed and vary during the various phases of the menstrual cycle. For example, let’s take a menstrual cycle of 28 days as a standard, as follows.
1, FSH and LH basal values are 5-10 IU/L (measured on 2-3 days of menstruation), maintained at low levels and FSH>LH, with minimal fluctuations in FSH when ovarian function is normal.
2, 2-3 before ovulation (i.e. day 11-12 of menstruation) the two rise rapidly, with LH rising significantly and can reach 3-8 times the basal value, sometimes up to 160 IU/L or higher, thus forming a peak (called LH peak), and the easy conception day is 2 days after the peak. In this way, it is also possible to guide the infertility patient to have intercourse according to the LH peak to increase the chance of conception. In contrast, FSH changes only about twice the basal value, rarely 30 IU/L. 3. FSH and LH drop rapidly after ovulation.
What is the significance of FSH and LH when they are not normal values?
The hypothalamus, pituitary gland and ovaries are the gonadal axis of women, and they regulate and influence each other. It is like the relationship between top leaders, officers and employees. A few cases are cited as follows.
1, premature ovarian failure (POF): when FSH40IU/L, LH elevated or 40IU/L, it can be considered high gonadotropin (Gn) amenorrhea, that is, ovarian failure, if it occurs before the age of 40, known as premature ovarian failure.
2, low Gn amenorrhea: both FSH and LH 5IU/L is low Gn amenorrhea, suggesting hypothalamus or pituitary hypofunction.
3, poor ovarian reserve function (DOR): FSH/LH2~3.6 or FSH12IU/L, next cycle recheck, 12IU/L continuously (FSH can be in normal range), suggest DOR, which is an early manifestation of poor ovarian function. elevated FSH/LH only reflects DOR, not the ability to conceive, once ovulation, the desired pregnancy rate can still be obtained.
4. polycystic ovary syndrome (PCOS): LH/FSH2~3, can be used as the main indicator for the diagnosis of PCOS (basal LH level of 10IU/L is considered elevated, or LH maintains normal level, while basal FSH is relatively low level, it forms an elevated LH to FSH ratio.) LH has the function of stimulating androgen synthesis, high LH leads to high androgen i.e. excessive androgen synthesis, and high High LH leads to hyperandrogenism, i.e. excessive androgen synthesis, and high androgen is an important causative factor for PCOS.
5, check 2 times basal FSH>20IU/L, can be considered as insidious stage of premature ovarian failure, suggesting possible amenorrhea after 1 year.
Conclusion
To understand LH and FSH, it is important to pay attention to their changes at different moments of menstrual cycle, so as to detect problems in time, prevent and treat them in time, and try to “prevent the disease before it happens, and prevent the change after it happens”, so as to protect women’s health together.