What is an anti-müllerian hormone (AMH) test?

An anti-müllerian hormone (AMH) test measures the amount of AMH in a blood sample. In males, AMH is made by the testicles (or testes), which are glands that make sperm and male hormones. In females, the ovaries make AMH. The ovaries are glands where eggs form and female hormones are made.

AMH plays different roles in males and females and normal levels of AMH vary with your sex and your age. Measuring AMH levels can provide information about a variety of reproductive health conditions.

In unborn babies, AMH helps form the male and female reproductive organs. The sex of unborn babies is set by the chromosomes they inherit from their parents. Male babies have XY chromosomes and female babies have XX chromosomes. But the development of their reproductive organs and genitals is affected by hormones, including AMH.

In the early weeks of pregnancy, both male and female babies have a set of ducts (tubes) called Müllerian ducts. Normally, male babies make high levels of AMH in their testicular tissue. The AMH makes the Müllerian ducts shrink and helps male organs to grow. AMH levels stay high in male children until puberty when they begin to decrease.

Unborn female babies have very low levels of AMH. This allows the Müllerian ducts to develop into the uterus, fallopian tubes, and the upper part of the vagina. AMH stays low in female children. At puberty, follicles inside the ovaries begin to make more AMH. Follicles are small sacs in the ovaries that hold immature eggs.

In healthy females of childbearing age, higher levels of AMH mean that the ovaries have a larger supply of eggs. As females age, the number of eggs decreases, which causes AMH levels to decrease. At menopause, no eggs are left, and AMH levels drop to zero.

Other names: AMH hormone test, müllerian-inhibiting hormone, MIH, müllerian inhibiting factor, MIF, müllerian-inhibiting substance, MIS

What is it used for?

AMH tests are mainly used with other tests to make decisions about treating female infertility (not being able to get pregnant). If you're having infertility treatment, AMH testing can:

• Check how many eggs you have left in your ovaries. This is called your "ovarian reserve." It's normal for your ovarian reserve to decrease with age. An AMH test can tell you the size of your ovarian reserve, but it can't tell you about the health of your eggs or predict whether you'll be able to get pregnant.

• Predict how well you may respond to fertility medicine. Normally, your ovaries prepare one egg for fertilization each month. If you're using in vitro fertilization (IVF) to have a baby, your health care provider will prescribe fertility medicine to make your ovaries prepare many eggs at the same time. The eggs are removed and mixed with sperm to make embryos outside of your body. Then the embryos are either frozen or put into the uterus to start a pregnancy.

  Testing your AMH level helps your provider know what dose of fertility medicine you may need to get the best response.

In females, AMH testing may also be used to:

• Find out if you're getting close to menopause or have already begun menopause. As you approach menopause your egg supply shrinks and AMH levels drop. AMH levels can be used to check for premature menopause (before age 40) and early menopause (before age 45). But an AMH test can't predict when you'll actually reach menopause. The average age of menopause is 52.

• Help diagnose and monitor problems with the ovaries that cause high AMH levels.
  These include:
  • Polycystic ovary syndrome (PCOS), a hormonal disorder that can cause infertility
  • Certain types of ovarian cancer

For babies and children, an AMH test may be used:

• To check for healthy testicles in a male baby or child that may have undescended testicles. This is a condition where the testicles fail to move from the belly, where they develop before birth, into their proper place in the scrotum. Healthy testicles in a male baby produce AMH. So, normal AMH levels mean that the baby has healthy, working testicles, but they just haven't dropped into the scrotum. Little to no AMH is a sign of other conditions that need more testing.

• To learn more about a baby born with genitals that aren't clearly male or female. This condition is called "atypical genitalia." In the past, it has been called "ambiguous genitalia" or "intersex." There are many types of atypical genitalia that have different causes. For example, problems with AMH and other hormones in a male baby can lead to the development of internal female reproductive organs and external genitals that don't look typical.

  An AMH test can show whether the baby has any working testicular tissue. This information can help diagnose the cause of the problem. The test is usually done with other tests, including chromosome testing, other hormone tests, and ultrasound scans to check for sex organs and glands inside the body.

Why do I need an AMH test?

If you're female, you may need an AMH test if you:

• Are having fertility problems. You may need an AMH test to:
  • Find out if your egg supply is normal for your age.
  • Plan in vitro fertilization (IVF) treatment. Higher levels of AMH mean that you're likely to respond to fertility medicine and you may only need a small dose. Low levels of AMH may mean need higher doses to respond.
• Have symptoms of polycystic ovary syndrome (PCOS), including:
  • Irregular menstrual periods, or no periods at all (amenorrhea)
  • Acne
  • Too much hair on the face, chest, stomach, or thighs
  • Hair loss on the head (male pattern baldness)
  • Weight gain
  • Dark patches of skin
• Are being treated for certain types of ovarian cancer. AMH testing can show if your treatment is working. After treatment the test can show whether cancer has returned.

A male baby or child who doesn't have testicles in the scrotum may need an AMH test to help find out if there are healthy testicles inside the body.

A baby with genitals that aren't clearly male or female may need an AMH test along with other tests to help diagnose the cause of the disorder and confirm the sex.

What happens during an AMH test?

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

Will I need to do anything to prepare for the test?

You don't need any special preparations for an AMH test.

Are there any risks to the test?

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

What do the results mean?

What the AMH test results mean depends on the reason the test was done:

If you're healthy and trying to get pregnant, ask your provider to explain what your AMH test results mean for your fertility based on your age and other test results. In general, a high level of AMH means you have more eggs available, and a low level means your egg supply is shrinking and your time to get pregnant may be shorter.

If you were tested for polycystic ovary syndrome (PCOS), a high level of AMH is a sign that you may have the disease. An AMH test alone cannot diagnose PCOS. There is no cure for PCOS, but symptoms can be managed with medications and/or lifestyle changes.

If you were tested for menopause, low AMH may mean you're getting close to menopause. But AMH test results can't predict how long you have until menopause. If your test result showed no AMH in your blood, it means you are in menopause. If you're younger than age 40 and have symptoms of menopause, an AMH level that's lower than average for your age may be a sign of primary ovarian insufficiency.

If you are being treated for ovarian cancer, a decrease in AMH usually mean that your treatment is working. If AMH increases, it may mean your treatment isn't working or cancer has returned.

If a male baby or child is tested for undescended testicles:

• Normal AMH levels mean the baby has working testicles, but they are not in the right location. This condition can be treated with surgery and/or hormone therapy.
• Little or no AMH may mean the testicles are not working or missing completely. This may be caused by a change (mutation) in the AMH gene. The baby may have atypical internal female reproductive organs with normal male genitals.

If a baby is tested because of genitals that aren't clearly male or female, the meaning of AMH test results depends on the results of other tests.

If you have questions about test results, talk with your provider.

Learn more about laboratory tests, reference ranges, and understanding results.