Luteinizing hormone or LH hormone test is done to check the functioning of ovaries in women and testes in men. It is one of the gonadotrophic hormones released by the pituitary gland, just like follicle stimulating hormone.
LH is important for the normal development and functioning of sexual organs in both men and women. Specifically, it is responsible for the maturation of primordial germ cells (which are the precursors of sperm and eggs).
Additionally, in women, LH helps to regulate the periods as it influences both the ovulation and the implantation of the embryo in the uterus, after fertilization.
In children, the level of LH rises shortly after birth and then falls sharply within 6 months for boys and 2 years for girls. Around 8 years of age, the levels of LH again start to rise signaling the beginning of puberty and the appearance of secondary sexual characteristics.
LH is also known as Lutropin and Interstitial Cell Stimulating Hormone (ICSH).
What is the use of LH hormone test?
An LH test is usually done along with FSH and other sexual hormones and these tests are used to check your sexual function, reproductive potential.
LH test in women is often used to:
- Find the reason or infertility
- Predict the time of ovulation (release of egg from the ovaries)
- Check the functioning of ovaries
- Find the reason for irregular or abnormal menstruation
- Predict the onset of perimenopause or menopause
LH test in men is used to:
- Diagnose infertility
- Find the cause of low sperm count
- Find the reason for low sex drive
- Check the functioning of testicles
It is also used in both men and women to check the normal functioning of pituitary and hypothalamus glands, as any defects in the, will affect the production of LH.
In children, LH test is used to check for early onset of puberty (before 9 years in girls and 10 years in boys) or delayed puberty (after 13 years in girls and 14 years in boys).
When should you do the LH test?
The LH test will be advised if you:
- Are struggling to conceive: If you’re facing infertility and have not been able to conceive even after 12 months of trying,
- Have menstrual cycle irregularities: If your periods are not regular, are too short or abnormally long, LH test will be advised among others
- Are nearing menopause: The value of LH and FSH rises as a woman approaches menopause, so the test is useful in confirming the reason for absence of periods
- Have reduced sex drive: In men, a lowered sex drive could indicate problems of the fertility system
- Have reduced sperm count: LH has an important role in the maturation of the sperm and a reduced sperm count may call for a hormone test
- Have pituitary gland problems: Pituitary dysfunction is indicated by the symptoms of weakness, fatigue, excessive weight-loss or reduced appetite along with any of the signs above. Since LH is made and released by the pituitary, any dysfunction of the gland would result in lower levels of the hormone.
- Pubertal problems in children: Precocious or delayed puberty in children may be a warning of a more serious problem of the hypothalamus or pituitary gland, or the sexual organs like the ovaries or testicles. LH and FSH levels in blood can help with differential diagnosis and to determine the actual cause of the problem. Signs of puberty in children are development of secondary sexual characteristics such as:
- Starting of periods and breast enlargement in girls
- Deep voice, facial hair, and growth of testicles in boys
LH testing details
When to get the LH test done?
Just like FSH and estradiol, the LH test is also preferably done on day 3 of the menstruation cycle. Normally, the results from day 2-day 4 are acceptable.
At this time, your body will have to produce more LH if your fertility is on the decline or your ovarian reserves are low.
A small blood sample is drawn from a vein your arm via a thin needle. The test can also be done via a prick test via an at-home testing kit. LH levels can also be tested with a urine sample, but it is less common.
At-home testing for LH is available in some locations; get in touch to learn more.
What preparations are required before the LH test?
If you’re taking any birth control or other hormone pills, you will be asked to stop any such medication at least four weeks before the LH test. These medications may lower your natural LH levels.
You must discuss your current medication with your doctor before doing the blood test for luteinizing hormone.
How long do the results take?
It normally takes only a day or two for a lab to send your LH results.
How does the Luteinizing hormone work?
The Luteinizing hormone in the body is regulated by a complex hypothalamic-pituitary-gonadal axis. Hypothalamus releases the Gonadotropic releasing hormone (GnRH), which stimulates the pituitary to release the LH in the bloodstream.
This LH, in women, signals the ovaries to produce estradiol in the follicular phase (14 days) of the menstrual cycle. Towards the end of this phase there is a surge in LH (along with FSH), which causes the mature ovarian follicle to tear and release an egg.
In the next part of the menstrual cycle—the luteal phase—the remnants of the ruptured ovarian follicle form corpus luteum, which secretes another hormone, called progesterone. This progesterone helps build your uterine lining during the early stages of the pregnancy, if the released egg is fertilized.
The luteinizing hormone in men stimulates the Leydig cells in the testes to produce testosterone, which in turn, regulates spermatogenesis (the production of sperm).
What are the normal levels of LH?
|LH in a woman’s Follicular phase||1.37 to 9 mIU/ml|
|Midcycle peak||6.17 to 17.2 mIU/ml|
|Luteal phase||1.09 to 9.2 mIU/ml|
|Postmenopausal women||19.3 to 58 mIU/ml|
|LH in men||1.42 to 15.4 mIU/ml|
There is a vast range of values of LH (depending upon the assay being used by your lab) that are considered normal on different days of your cycle. You must ask your lab for a reference range and discuss the results with a qualified doctor, before making any conclusions about your LH report.
What is the ideal level of LH for IVF?
Even though there is no definitive cut off value for follicular phase LH that warrants the cancellation of an IVF cycle, normally LH levels of between 2.4mIU/ml and 12.6 mIU/ml are considered optimal. Day 3 level of luteinizing hormone that is around 7 mIU/L is considered good but it can vary with the assay being used by your lab.
LH levels higher than FSH can be an indication of PCOS. High levels of LH can cause premature ovulation, which means poor egg quality and early stimulation of progesterone production by the ovaries. This makes the uterine lining inadequate for receiving the embryo.
Some experts have advocated for earlier egg retrieval in patients with premature LH surge but a study of 164 patients found that an earlier OPU may not help reduce the cancellations of IVF. However, more research is needed in this direction.
If we have enough data to determine the optimal values of LH, FSH, and progesterone before fertilization, it may enhance the overall success rates of IVF.
What is LH surge?
LH surge is the spike in luteinizing hormone that happens just before ovulation, when LH levels rise to around 45mIU/ml but that value is highly variable. LH levels have been reported to be 6.5mIU/ml – 101mIU/ml on the day before ovulation.
It is to be noted here that the range of LH levels required to trigger ovulation is pretty wide— During the surge, LH levels may rise to only double for some women and go up almost 15-fold for others.
LH surge happens mid-cycle and is an indication of ovulation for most women. It is used to time the sex or insemination in artificial insemination, when you’re trying to conceive.
Ovulation sometimes even happens despite no significant LH surge but researches in a study of 46 women noted that the pre-ovulation rise of E1C happened in all cycles, confirming that estrogen plays an important role in stimulating the LH surge.
What are the expected LH levels by age?
|Menstruating women (10 – 45 years)||5 – 25 mUI/ml|
|After menopause (45+ years)||19 – 100mUI/ml|
|LH levels in adult men||1.8 – 8.6mUI/ml|
LH in children generally remains low.
In infertile women, LH levels were found to start rising at around 30 years, with marked increase at around 35-36 years, and even significant jump after 40. This study involved 500 infertile women, who had regular menstrual cycles.
In what conditions is LH low?
Low LH levels in adults are usually due to:
- Malnutrition or eating disorders
- Pituitary or hypothalamus dysfunction
Women with low LH may have irregular or absent periods (amenorrhea).
In children, low LH levels (along with low FSH) is often sign of delayed puberty, which may be caused by:
- Turner syndrome or disorder of the ovaries in girls
- Klinefelter’s syndrome or disorder of the testicles in boys
- Hormone deficiencies
- Eating disorders
- Some infection
What if the LH is high?
In women, high LH levels could indicate:
- Problems of the ovaries or anovulation
- Age related infertility
- The beginning of perimenopause or menopause
- Polycystic ovarian syndrome (PCOS)
- Turner syndrome—a genetic disorder that disrupts normal sexual development in women and often leads to infertility
In men, high LH levels are an indication of:
- Testicle damage due to excessive alcohol abuse, chemo or radiotherapy
- Klinefelter’s syndrome—a genetic disorder that causes infertility by disrupting normal sexual development in males.
In children, high LH (along with high FSH) often is a sign of beginning of puberty.
In cases of precocious puberty (before 9 years in girls and 10 years in boys), it could indicate:
Pituitary or hypothalamus problems due to some brain injury or disorder of the central nervous system.
For more information about Luteinizing hormone (LH) testing and to order your LH test, get in touch. *t&c apply.
Nedresky D, Singh G. Physiology, Luteinizing Hormone. [Updated 2020 Sep 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan: https://www.ncbi.nlm.nih.gov/books/NBK539692/
Choi, M. H., Cha, S. H., Park, C. W., Kim, J. Y., Yang, K. M., Song, I. O., Koong, M. K., Kang, I. S., & Kim, H. O. (2013). The effectiveness of earlier oocyte retrieval in the case of a premature luteinizing hormone surge on hCG day in in vitro fertilization-embryo transfer cycles. Clinical and experimental reproductive medicine, 40(2), 90–94. https://doi.org/10.5653/cerm.2013.40.2.90
Sönmezer, M., Pelin Cil, A., Atabekoğlu, C., Ozkavukçu, S., & Ozmen, B. (2009). Does premature luteinization or early surge of LH impair cycle outcome? Report of two successful outcomes. Journal of assisted reproduction and genetics, 26(2-3), 159–163. https://doi.org/10.1007/s10815-009-9299-5
Susanna J. Park, MD; Laura T. Goldsmith, Ph.D.; Joan H. Skurnick, Ph.D.; Andrea Wojtczuk, MS; Gerson Weiss, MD. Characteristics of the urinary luteinizing hormone surge in young ovulatory women April 16, 2007 DOI: https://doi.org/10.1016/j.fertnstert.2007.01.045
Ahmed Ebbiary, N. A., Lenton, E. A., & Cooke, I. D. (1994). Hypothalamic-pituitary ageing: progressive increase in FSH and LH concentrations throughout the reproductive life in regularly menstruating women. Clinical endocrinology, 41(2), 199–206. https://doi.org/10.1111/j.1365-2265.1994.tb02530.x