What is an Anti-Mullerian Hormone?

An anti-mullerian hormone (AMH) is a protein produced by the egg follicles in a woman's ovaries. These follicles mature in order to release an egg into the fallopian tube during ovulation. In women experiencing infertility, AMH levels can be tested to determine if a woman’s ovaries are producing eggs and can indicate the number of remaining eggs. An anti-mullerian hormone test can also indicate if a woman suffers from Polycystic ovarian syndrome (PCOS).

AMH, also known as the Mullerian inhibiting factor or the Mullerian-inhibiting hormone, can be an indicator to determine if in vitro fertilization or other fertility procedures will be successful. A woman’s ovaries contain all the follicles and eggs a woman will produce in her lifetime. With each menstrual cycle, an egg is released and the follicles that matured during the cycle are lost. As a woman ages, the number of healthy eggs capable of being fertilized decreases.

In the past, the 3 FSH test, completed on the third day of a woman’s menstrual period, was done to determine a woman’s ovarian reserve. The anti-mullerian hormone test has gained popularity as being a more consistent and correct indicator of a woman’s fertility. An AMH test can be completed on any day of a woman’s cycle, and the levels do not vary from cycle to cycle. The FSH test results, on the other hand, depend upon a woman’s estrogen level being low when the test is performed.

An AMH test determines the level of early antral follicles, which mature into follicles that contain eggs to be released during ovulation. Women with lower AMH levels, and therefore lower follicle counts, produce fewer oocytes each month than women with higher levels of the hormone. The results of this test can show how responsive a woman’s body will be to fertility treatments. Usually, a physician will not rely solely upon the results of the AMH test during an assessment of fertility. A transvaginal ultrasound usually is also performed to determine the overall number and health of antral follicles.

The anti-mullerian hormone test can also determine if a woman suffers from PCOS, a condition in which small cysts grow on the ovaries. PCOS causes a hormone imbalance and may result in the loss of a menstrual cycle. PCOS is one of the leading causes of infertility. An AMH test for a woman with PCOS will show high levels of the hormone in the blood because the condition creates immature follicles, which are either never released from the ovaries or develop into cysts.