Luteinizing Hormone (LH)

What is Luteinizing Hormone?

LH refers to Luteinizing hormone. It is responsible for the release of an egg from the ovary in women; and, the production of testosterone in men. This hormone is produced by the pituitary gland that is located at the base of the brain; and, controlled by the hypothalamus. During menstruation, levels of hormones fluctuate throughout every cycle. Every cycle is divided into two phases: the follicular and the luteal phase. Every phase lasts for a period of 14 days. When the first, follicular, phase ends; a surge of LH happens casing ovulation: the egg follicle ruptures and the egg is released. During the second phase, the egg becomes the corpus luteum that becomes stimulated and secretes progesterone. This stimulation is caused by the LH that starts declining. For men, the role of the LH is different. It is responsible for stimulating Leydig cells in the testicles. As a result, testosterone will be produced.

LH is considered to be a gonadotropin as it plays a major role in the development of the gonads in men and women. Despite the fact that LH is normally associated with women, men also produce it and need it for a proper reproductive process. This hormone helps in the production of sperm.

Why take the LH test?

You need to get tested for the LH if there are doubts that you may be infertile, whether you are a man or a woman. You may be considered infertile if you have been having unprotected sex, on a regular basis, for up to a year without getting pregnant. This is the main sign of infertility. Other signs that may accompany are having abnormal periods, irregular ones, or their absence; skin changes leading to acne, low sex drive, dark hair growth on the lips, chest and chin in women, as well as hair thinning. Symptoms that may accompany infertility in men can be vague; and, include changes in hair growth and sexual desire, swelling in the testicles, having small firm testicles, as well as facing problems with erection and ejaculation. In case such symptoms are noticed, getting tested for LH is recommended.

The test is also needed to check the proper functioning of the pituitary gland and the hypothalamus. Your LH levels also need to be checked if you have symptoms such as irregular menstrual periods, absence of menstruation, low testosterone levels, low sex drive as well as low muscle mass in men. Symptoms of low testosterone include feeling tired and weak, depressed, experiencing erectile dysfunctions and noticing changes in sleep habits.

If you feel weak and tired, lose weight for no reason, and have a decreased appetite; then, you may have problems in your pituitary gland that may be detected by testing your LH levels.

The LH test is considered to be a predictive test indicating ovulation; however, it cannot confirm if ovulation occurred.

What causes the levels of LH to change?

Certain drugs and medications can alter your test results. For example, anticonvulsants, clomiphene and naloxone can increase your levels. On the other hand, digoxin, oral contraceptives, and hormone treatments may lower your levels. Any hormonal therapy or oral contraceptive may need to be stopped up to four weeks prior to the test.

Do not get tested for LH if you have done a recent nuclear medicine scan (less than seven days), especially if it was done by radioimmunoassay.

What do the LH test results mean?

Once the results are ready, they are sent to you by email. You need to understand that LH normal values depend on your menstruation phases and menopause. From another angle, values differ between sexes. In general, these are the normal values depending on your age and status.

• For women in the follicular phase (menstruating still): normal LH values need to be between 1.8 and 12.5 IU/L
• For women at their peak of their menstruation: normal values should be between 8.7 and 76.3 IU/L.
• For women in their lutea phase (menstruation): normal LH values are between 0.5 and 16.9 IU/L.
• Women, who are pregnant, have their normal LH levels below 1.5 IU/L
• Post-menopausal women have normal LH values between 15.9 and 54 IU/L.
• Women using contraceptives have normal LH values between 0.7 and 5.6 IU/L.
• Men, who are between ages of 20 and 70 years, have normal LH levels between 0.7 and 7.9 IU/L.
• Men who are older than 70 years, have normal LH values between 3.1 and 34.0 IU/L.

If your LH levels are higher than normal; then, it may be due to menopause (the period just before or just after), Turner syndrome (that is a rare condition when women do not have two X chromosomes), ovarian hypofunction (when the ovaries are making too little hormones, or none), as well as polycystic ovary syndrome (imbalance of female sex hormone caused by ovarian cysts). Higher levels may indicate that a woman, who is still of childbearing age, is not ovulating.

A study published by the journal of human reproductive sciences explained the effect of the LH on the reproductive system. The findings indicated that women who had high levels of LH had significantly low rates of fertilization. Another study added that such elevated levels, during the follicular phase, can cause detrimental effects. It was more likely for women who have LH levels less than 10 IU/L to get pregnant, while those who had levels above 10 IU/L were more likely to have miscarriages.

For men, higher than normal levels may indicate primary testicular failure. This condition can be due to either developmental defects of the testicles or trauma. Examples of problems include anorchia (absence of testes or non-functioning testes), Klinefelter syndrome (genetic problems) or multiple endocrine neoplasia (overreactive endocrine glands or endocrine tumor). In addition, elevated levels can also be caused by viral infections (like mumps), trauma, exposure to radiation, chemotherapy, autoimmune diseasesor germ cell tumors.

Lower than normal levels of LH can be due to hypopituitarism, a condition when the pituitary gland does not produce enough or produces very little hormones. When the hormone is underproduced, it leads to a loss of function in the gland or organ it is controlling. For children, high levels of LH may indicate precocious puberty, especially when accompanied by delayed or premature secondary sexual characteristics. Such a condition is more common among girls.

Where can I get a LH test near me?

Please use our Lab Locator to find find a convenient testing location.

Reviewed By: Dr. Kurt Kloss, MD
Last Reviewed Date: Oct 24, 2019