Luteinizing Hormone LH

Also Known as: lutropin, interstitial cell-stimulating hormone, LH test

What is a Luteinizing Hormone (LH) test?

This test measures the luteinizing hormone (LH) levels in your blood. Your pituitary gland which is a small gland underneath your brain produces LH. The hypothalamus in the brain, the pituitary gland, and the hormones generated by the ovaries and testicles all work together to control the production of LH. LH is important for sexual development and functioning such as :

In women, it assists in the regulation of the menstrual cycle, stimulates the egg to be released (ovulation) from the ovary, and also signals the ovaries to produce the hormone estrogen.
In men, LH levels do not fluctuate much normally and they play their part in stimulating the testicles to produce testosterone, which is necessary for sperm production
LH levels in children are typically low during early childhood and begin to rise a few years before puberty. A variety of problems such as infertility, menstrual irregularities, early or delayed puberty, and low sex drive can also be caused by the presence of too much or too little LH levels in the blood.

What is the test used for?

To control sexual functioning, an LH test works in combination with another hormone called follicle-stimulating hormone (FSH). Depending on whether you are a woman, a man, or a child, these tests are used in different ways.These tests are most commonly used in women to:

Assist in determining the cause of infertility.
Find out when ovulation (egg release) takes place; a time when you're most likely to conceive.
Determine the cause of irregular or stopped menstrual cycles.
Confirm that menopause (when a woman's menstrual periods have finished and she is no longer able to conceive) or perimenopause (transition period before menopause) has begun.

These tests are most commonly used in men to:

Assist in determining the cause of infertility.
Find out why your sperm count is low.
Find out why you have a low sex drive

These tests are most commonly used in children to diagnose early or delayed puberty.

If puberty begins before the age of nine in girls and before the age of ten in boys, it is called early puberty.
Puberty is considered delayed if it has not begun by the age of 13 in girls and 14 in boys.

Why and when do you need this test?

If you are a woman, this test may be required if:

You have been trying for a year and have not been able to conceive.
Your menstrual cycle is not consistent ( irregular).
Your periods have stopped (menopause). You can use this test to identify if you have reached menopause or are in the perimenopause stage.

If you are a man, this test may be required if:

After a year of trying, you haven't been able to get your spouse pregnant.
Your sexual desire has been reduced

If you experience symptoms of a pituitary disorder, both men and women may require this test. Some of the symptoms stated above are included, as well as:

Fatigue
Weakness
Loss of weight
Loss of appetite

An LH test may be required if your child does not appear to be commencing puberty at the appropriate age. Signs of puberty include:

Breast enlargement in young girls
Pubic hair growth
Testicles and penis growth in boys
Beginning of menstrual cycle in girls

What kind of sample is required for the test?

A small needle will be used by a healthcare professional to obtain a blood sample from a vein in your arm. A small amount of blood will be collected into a test tube or vial once the needle is inserted. When the needle goes in or out, it may sting a little. It normally takes less than five minutes to complete this process.

Do you need to prepare for the test?

If you are a woman who has not yet reached menopause, your doctor may suggest that you have your test at a specified point in your menstrual cycle. If there are any other special instructions to follow regarding additional testing, your health care provider will inform you.

Are there any risks to this test?

Having a blood test carries relatively little risk. You may experience little pain or bruising where the needle gets inserted, but most symptoms disappear quickly.

What do the test results mean?

Your results will differ depending on whether you are a woman, a man, or a child.
If you are a woman, elevated LH levels could indicate that you:

Are not ovulating. If you are of childbearing age, this could indicate an issue with your ovaries. If you're over 40, it is possible you have started menopause or are in the perimenopause stage.
Have been diagnosed with polycystic ovary syndrome (PCOS): a common hormone disease that affects women of childbearing age and is one of the leading reasons for infertility among women.
Have Turner syndrome: a hereditary condition that affects female sexual development often causing infertility issues.

If you're a woman, low LH levels could indicate:

Your pituitary gland is not functioning properly.
You are suffering from an eating disorder.
You are malnourished.

If you are a man, elevated LH levels could imply one of the following:

Chemotherapy, radiation, infection, or alcohol abuse may have affected your testicles.
Autoimmune Disease
Germ Cell tumor
Failure to develop normal gonads
You may have Klinefelter's syndrome: a hereditary disease (chromosome disorder) affecting male sexual development and may cause infertility issues.

If you are a man, low LH levels may indicate

A disorder of the pituitary gland or hypothalamus

High levels of LH and follicle-stimulating hormone (FSH) in children may indicate that puberty is about to begin or has already begun. If this occurs before the age of nine in a girl or before the age of ten in a boy (precocious puberty), it could be an indication of:

A condition that affects the central nervous system e.g central nervous tumor, meningitis, encephalitis)
A brain injury or trauma

Low levels of LH and follicle-stimulating hormone in children may indicate a delay in puberty. Puberty can be delayed due to a variety of factors, including:

A condition affecting the ovaries or testicles.
Turner syndrome affecting young girls.
Klinefelter's syndrome in boys
A chronic infection.
Deficiency of hormone
An eating disorder

Should you have any questions regarding your results you should consult your healthcare provider.

Related Tests:
Follicle stimulating Hormone (FSH), Testosterone, Progesterone, Estrogens, Androstenedione, Semen Analysis, Anti-Müllerian Hormone, Prolactin, Sex Hormone Binding Globulin (SHBG)

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