Lutenizing Hormone (LH) Test

Lutenizing hormone (LH) is a hormone that is vital for reproduction. It is produced by your pituitary gland. LH helps regulate your menstrual cycle and ovulation. A rise in LH (called the LH surge) triggers ovulation.

Why Would You Have LH Checked?

LH can be used to determine when you are ovulating. This information can help you plan intercourse if you are trying to become pregnant.

You will probably have your LH checked if you are having trouble becoming pregnant. It gives information about your ovarian reserve. If you are not ovulating, your LH levels can help determine if it is a primary failure (failure of the ovaries themselves) or secondary failure (failure of the ovaries related to problems with the pituitary gland or hypothalamus). It can also be used to monitor your response to ovarian stimulation.

If you are not having your period or are having irregular cycles, you might have your LH checked to try to find out what the problem is. It can also help determine if you are going through menopause.

When Should You Have Your LH Levels Checked?

You should have your LH levels checked midway through your cycle (day 14 of a 28 day cycle). This is because the LH surge triggers ovulation.

What Does the LH Test Look For?

The LH test measures the amount of LH in the blood or urine.

If your LH levels are high, it could mean a number of things. High levels of LH are normal if you are in menopause. If you are younger than 40, high LH levels could suggest premature menopause, polycystic ovary syndrome (PCOS), or a genetic or congenital condition that affects the production of hormones. High levels at times outside of the LH surge can interfere with ovulation and menstruation, contributing to infertility.

If your LH levels are low, you will usually not be having your period. Because LH triggers ovulation, low levels of LH can prevent ovulation and thus pregnancy. Low levels of LH are common in women with eating disorders, female athlete triad, high levels of stress and disorders of the pituitary or hypothalamus.

LH testing is usually done in conjunction with other hormone tests such as FSH, testosterone, estradiol and progesterone. The results of these other tests will help determine next steps.