Luteinizing hormone (LH): what it is and why it is high or low

Luteinizing hormone, also called LH, is a hormone produced by the pituitary gland and, in women, is responsible for the maturation of follicles, ovulation and production of progesterone, playing a fundamental role in a woman’s reproductive capacity. In men, LH is also directly related to fertility, acting directly on the testicles and influencing sperm production.

In the menstrual cycle, LH is found in higher concentrations during the ovulatory phase, however it is present throughout a woman’s life, having different concentrations according to the phase of the menstrual cycle.

In addition to playing an important role in checking the reproductive capacity of men and women, the concentration of LH in the blood helps in the diagnosis of pituitary tumors and changes in the ovaries, such as the presence of cysts, for example.

What is it for

The LH dosage is used to:

• Diagnose infertility;
• Assess the man’s sperm production capacity;
• Check whether the woman has entered menopause;
• Assess the causes of the absence of menstruation;
• Check whether there is adequate production of eggs in the case of women;
• Assist in the diagnosis of pituitary tumor, for example.

In men, LH production is regulated by the pituitary gland and acts directly on the testicles, regulating sperm production and the production of hormones, mainly testosterone. In women, the production of LH by the pituitary gland stimulates the production of progesterone, mainly, and estrogen, which is essential for pregnancy.

To assess the reproductive capacity of both men and women, the doctor may also request a measurement of FSH, which is a hormone that is also present in a woman’s menstrual cycle and influences sperm production. Understand what it is for and how to understand the FSH result.

LH reference values

The reference values ​​for luteinizing hormone vary according to age, gender and phase of the menstrual cycle, in the case of women, with the values ​​being:

• Children: less than 0.15 U/L;
• Men: between 0.6 – 12.1 U/L;
• Women in ffollicular ase: between 1.8 and 11.8 U/L;
• Women at ovulatory peak: between 7.6 and 89.1 U/L;
• Women in the luteal phase: between 0.6 and 14.0 U/L;
• Menopause: between 5.2 and 62.9 U/L.

The analysis of the test results must be carried out by the doctor, as it is necessary to analyze all the tests together, as well as compare them with the tests carried out previously.

When LH values ​​are below the reference value, it may be indicative of:

• Change in the pituitary gland, resulting in decreased production of FSH and LH;
• Deficiency in the production of gonadotropin (GnRH), which is a hormone produced and released by the hypothalamus and whose function is to stimulate the pituitary gland to produce LH and FSH;
• Kallmann syndrome, which is a genetic and hereditary disease characterized by the absence of GnRH production, which leads to hypogonadotropic hypogonadism;
• Hyperprolactinemia, which is an increase in the production of the hormone prolactin.

The decrease in LH can lead to a decrease in sperm production in men and in the absence of menstruation in women, a situation known as amenorrhea, and it is important to consult a doctor so that the best treatment can be indicated, which is normally done with the use of hormonal supplementation. .

High luteinizing hormone

The increase in LH concentration may be indicative of:

• Tumor in the pituitary gland, with an increase in the secretion of GnRH and, consequently, LH;
• Early puberty;
• Testicular insufficiency;
• Early menopause;
• Polycystic Ovary Syndrome.

Furthermore, the LH hormone may be increased during pregnancy, because the hCG hormone can imitate LH and may appear elevated on tests.