Men are constantly manufacturing new sperm, with millions in reserve. Eggs are more resource-intensive to produce, and far fewer in number. A woman is born with the total number of eggs she will ever have in her life. This means that when the eggs are gone, there is no chance of fertility. While men's fertility declines somewhat with age due to factors such as lowered sperm count and the accumulation of genetic mutations that lower sperm quality, women's fertility becomes completely nonexistent at menopause, and drops precipitously in the years preceding menopause.

Sometimes, a woman's egg supply is lower than would otherwise be expected based on her age. Diminished ovarian reserve can reduce or completely eliminate a woman's fertility. And because fewer eggs can quickly mean no eggs at all, it's important to identify the issue as early as possible.

Anti-Müllerian Hormone (AMH) testing is a simple way to assess a woman's ovarian reserve, and to diagnose issues such as early menopause or diminished ovarian reserve.

What is Anti-Müllerian Hormone (AMH)?

Immature cells lining egg sacs and follicles secrete Anti-Müllerian Hormone (AMH) into the ovary and bloodstream. Because AMH levels are relatively consistent throughout the menstrual cycle, AMH testing can be done at any time during a woman's cycle. Though AMH won't directly reveal factors such as ovarian quality or delayed ovulation, it is an excellent proxy for measuring ovarian reserve. It can also provide information about how a woman's body will respond to fertility drugs used during an in vitro fertilization (IVF) cycle.

To assess a woman's current and future fertility, a doctor will compare her AMH levels to those of other women her age. Though AMH levels generally decline with age, a precipitous decline suggests something might be wrong, such as premature menopause or decreased ovarian reserve. Thus the higher AMH levels a woman has, the bigger her future fertility window may be. Knowing that a woman's AMH levels are dropping can help a doctor determine whether future tests are necessary, assess the value of an in vitro fertilization (IVF) cycle, and determine whether follicle-stimulating drugs or egg preservation may be appropriate. An AMH level greater than 1 generally suggests a reasonably high ovarian reserve.

Because some women continue to have normal menstrual cycles even with a diminished ovarian reserve, AMH testing is helpful in couples who have tried for longer than a year to get pregnant, who have up until now unexplained infertility, or whose blood tests show no major anomalies that would undermine fertility.

Before the AMH test became widely available, women considering IVF had to undergo a full IVF cycle to assess how their bodies would respond to IVF drugs. AMH makes it possible to determine whether a woman needs additional drugs, the likelihood of IVF success, and whether any underlying issues are contributing to a woman's fertility problems.

How is Anti-Müllerian Hormone (AMH) Testing Done?

The AMH test is a blood test using blood drawn from a vein. Though the procedure itself is simple, interpreting the results requires specific equipment. Thus you will have to specifically request the test from your doctor; it is not necessarily a part of routine fertility blood testing. You do not need to fast or take other special actions prior to the test, and the blood draw itself takes only a few minutes. You should have test results back in a week or so.

To get the best overall picture of a woman's fertility, AMH testing works best when done in conjunction with an antral follicle count test. Your doctor may advise other tests as well, particularly if you have not undergone extensive hormonal tests. This means that you may need to undergo testing at a specific point in your cycle, even though the AMH test can be done at any time. For example, if your doctor also wishes to test you for progesterone levels, he or she will likely order testing in the second half of your cycle.

Most research suggests that birth control pills do not affect AMH levels, but they can affect the levels of other hormones. Your doctor may request that you go off of birth control for up to three months. If you are taking other fertility drugs, be sure to tell your doctor, since you may need to stop taking them before undergoing fertility testing.