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Diagnostic Tests 2023

Horm&luteinizing circ;nium (LH): what é and why está high or low

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Horm&luteinizing circ;nium (LH): what é and why está high or low
Horm&luteinizing circ;nium (LH): what é and why está high or low

The luteinizing hormone, also called LH, is a hormone produced by the pituitary gland and which, in women, is responsible for the maturation of follicles, ovulation and progesterone production, playing a fundamental role in the reproductive capacity of women. In men, LH is also directly related to fertility, acting directly on the testes 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 having an important role in verifying 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. This exam is most requested by the gynecologist to check the he alth of the woman, being normally requested together with the dosage of FSH and the Gonadotropin Releasing Hormone, the GnRH.


What is it for

The dosage of luteinizing hormone in the blood is usually requested to check the person's reproductive capacity and help in the diagnosis of some changes related to the pituitary, hypothalamus or gonads. Thus, according to the amount of LH in the blood, it is possible:

  • Diagnose infertility;
  • Evaluate the man's ability to produce sperm;
  • Check if the woman has entered menopause;
  • Evaluate the causes of the absence of menstruation;
  • Check for adequate egg production 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 testes, regulating sperm production and the production of hormones, especially 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 the dosage of FSH, which is a hormone that is also present in a woman's menstrual cycle and influences sperm production. Understand what it's for and how to understand the result of FSH.

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 following values:

Children: less than 0.15 U/L;

Men: between 0.6 - 12.1 U/L;


  • Follicular phase: between 1.8 and 11.8 U/L;
  • Peak ovulation: between 7.6 and 89.1 U/L;
  • Luteal phase: between 0.6 and 14.0 U/L;
  • Menopause: between 5.2 and 62.9 U/L.

The analysis of the exam results must be done by the doctor, as it is necessary to analyze all exams together, as well as the comparison with the exams performed previously.


Low luteinizing hormone

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

  • Change in the pituitary, 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 by men and the absence of menstruation in women, a situation known as amenorrhea, and it is important to consult the doctor so that the best treatment is indicated, which is usually 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, of LH;
  • Precocious puberty;
  • Testicular failure;
  • Early Menopause;
  • Polycystic Ovarian Syndrome.

In addition, the LH hormone may be increased in pregnancy, because the hCG hormone can mimic LH, and may appear elevated in tests.

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