What is LH?
Luteinizing hormone (LH) is primarily a fertility hormone in both men and women. In women, LH affects the ovaries, stimulating ovulation and progesterone synthesis. In males, it affects the testes. LH has a role in puberty, menstruation, and fertility.
Why test LH?
LH is used as included in a panel of tests to evaluate a woman’s reproductive function and menstrual problems. Determining your blood LH levels can indicate underlying problems associated with several reproductive health issues. In women, reasons to test your LH include fertility issues, miscarriage, to check for perimenopause or menopause, or if you have irregular or absent menstrual periods or other suspected problems, e.g., Polycystic Ovarian Syndrome (PCOS).
In men, LH can be tested in men with signs of low testosterone levels, such as low muscle mass or a decreased sex drive. Experts disagree about the extent to which men should test their hormones as part of a fertility assessment. It is thought that, in the majority of cases, male hormones are not the cause of male infertility.
What causes low LH?
Low or high levels do not necessarily indicate a problem if there are no symptoms. If you are a woman low LH levels may mean that your pituitary gland is not working correctly, that you have an eating disorder, or that you are malnourished.
Low LH levels in men may indicate a pituitary gland or hypothalamus disorder. Low LH and FSH levels in children may be a sign of delayed puberty caused by ovarian or testicle disorder, Turner Syndrome (girls), Klinefelter's syndrome (boys), infection, hormone deficiency and eating disorders.
Symptoms of low LH
Symptoms of low luteinizing hormone (LH) can vary depending on the individual's age and sex. In women, low LH can lead to irregular or absent menstrual periods, infertility, and decreased sexual desire. In men, it can cause low testosterone levels, leading to symptoms such as decreased sex drive, erectile dysfunction, decreased muscle mass, fatigue, and infertility. In children, low LH levels can result in delayed or absent puberty.
What causes high LH?
The results of this test are complex and need to be looked at by your doctor considering other test results. LH is used alongside other tests. LH and FSH levels can help to distinguish between primary ovarian failure (direct ovarian failure or lack of ovarian development) and secondary ovarian failure (ovarian failure due to disorders of either the pituitary or the hypothalamus).
Secondary ovarian failure causes low levels of LH and FSH. Secondary ovarian failure indicates a problem with the pituitary or hypothalamus. In women who wish to get pregnant, several LH tests can help identify the surge before ovulation An LH surge indicates that ovulation has occurred.
You have more circulating LH than expected. High levels do not necessarily indicate a problem if there are no symptoms. The significance of LH results depends on a few factors, such as your gender and age. High LH levels in women may mean that you:
- are not ovulating. If you are of childbearing age, this may mean you have a problem in your ovaries. If you are older, it may mean you have started menopause or are in perimenopause.
- have polycystic ovary syndrome (PCOS). PCOS is a common hormone disorder affecting childbearing women. It is one of the leading causes of female infertility.
- have Turner syndrome, a genetic disorder that affects sexual development in females. It often causes infertility.
In postmenopausal women, an increase in LH levels may play a role in the development of Alzheimer’s Disease. LH promotes the deposition of amyloid β plaques in the hippocampus, as seen in Alzheimer’s Disease.
If you are a man, high LH levels may mean that your testicles were damaged by chemotherapy, radiation, infection, or alcohol abuse, or that you have Klinefelter's syndrome, which often causes infertility.
In children, high LH levels, along with high levels of follicle-stimulating hormone, may mean puberty is about to start or has already begun. Before age 9 for girls or age 10 for boys (precocious puberty), it may be a sign of a disorder of the central nervous system or a brain injury.
Symptoms of high LH
High luteinizing hormone (LH) levels in women can cause irregular menstrual cycles, infertility, and symptoms of PCOS like acne and excessive hair growth. In men, it may indicate testicular failure, leading to low testosterone, reduced muscle mass, fatigue, and infertility. In children, high LH can cause early puberty.
More information
LH levels should rise at mid-cycle, about 24 to 36 hours before ovulation occurs. High levels of LH on day 3 may indicate disorders such as polycystic ovary disease or ovarian failure. If you take hormonal contraceptives, the results of this test may not be accurate.
Preparations for this test
This test should not be performed during ongoing or after recently completed antibiotic treatment. For fertility evaluation, this test should be taken on day 3 (or at least between days 2-5). A woman’s menstrual cycle is measured from the first day of her period (blood flow, not spotting), so Cycle Day 3 is the third day of her period.
On the day of the test
Remember to take I.D. with you when going to take a test.