The U.S. Food and Drug Administration (FDA) recently approved the first blood test for helping to determine when a woman has entered menopause. The test measures the amount of anti-Müllerian hormone (AMH) in the blood.

AMH is a hormone produced by a woman’s ovaries that has a role in egg maturation and release (ovulation). AMH levels fall as menopause approaches and is one of several indicators healthcare practitioners have to determine whether a woman is approaching or is likely to have reached menopause. The FDA cautions that the AMH test should be used with other lab tests and assessments.

Menopause marks the end of a woman’s menstrual cycles and fertility. A woman is generally considered to be in menopause if she has not had a menstrual period in twelve months. Women usually begin the gradual transition to menopause (perimenopause) between ages 45 and 55. During this transition, levels of the hormone estrogen can fluctuate, and women may experience symptoms such as:

• Irregular or skipped periods
• Vaginal dryness
• Hot flashes
• Night sweats
• Trouble sleeping
• Mood changes
• Weight gain and slowed metabolism

Although menopause is a natural part of aging, it is associated with an increased risk of adverse health conditions. Decreased estrogen can put women at risk for bone loss (osteopenia) and osteoporosis, which can lead to bone fractures. Low estrogen may also contribute to unhealthy lipid levels and increased risk of heart disease.

Because of varying symptoms and ages when women enter menopause, the condition can be difficult to recognize. Women’s health experts say it is important to determine if a woman is in menopause to be sure that another condition, such as endometriosis or low thyroid hormone levels, isn’t responsible for the symptoms a woman may be experiencing. Knowing that menopause is arriving or has arrived also allows healthcare practitioners to discuss treatment options, including medications to prevent osteoporosis and to reduce cholesterol levels to help prevent risk of heart attacks and heart disease.

“Diagnostic results about a woman’s menopausal status may prompt discussions about [preventive] care for women experiencing menopausal symptoms,” said Courtney Lias, Ph.D. director of the Division of Chemistry and Toxicology Devices in the FDA’s Center for Devices and Radiological Health. “This test, when used in conjunction with other clinical assessments and laboratory findings, can help inform discussions about [preventive] care, such as ways to help prevent loss in bone mineral density or to address cardiovascular disease, both of which are known to increase after menopause.” adds Dr. Lias.

Until now, healthcare practitioners have determined if a woman was approaching menopause by discussing symptoms and in some cases doing blood tests including tests to check a woman’s levels of follicle-stimulating hormone (FSH), estrogen, and thyroid-stimulating hormone (TSH). FSH levels increase and estrogen levels decrease as women transition to menopause. Low levels of TSH, a sign of thyroid dysfunction, can cause symptoms like those associated with menopause.

Before approving the AMH test, the FDA reviewed data on 690 women ages 42 to 62, which showed that the test performed “reasonably well at determining levels of AMH in the blood and identifying women who had their last menstrual period (have reached menopause) and women who were more than five years away from their last menstrual period.”

The FDA says it’s important for healthcare practitioners to use the test results only as one piece of data when assessing a woman so that other potential causes of symptoms are not missed. It is also important that women who have not reached menopause and are not trying to get pregnant continue to use birth control. The test has not been approved for assessing fertility or for evaluating women planning or undergoing fertility treatments.