Anti-Mullerian Hormone (AMH)
Medically reviewed by Dr. Norbert Gleicher, MD, FACOG, FACS - Written by CHR Staff - Updated on September 3, 2020
What is AMH?
AMH (short for “anti-Mullerian hormone”) is a hormone secreted by the cells of the developing follicles (or egg sacks) in the ovaries. A good indicator of ovarian reserve, AMH is an integral part of fertility testing, along with other hormones that help to provide an overall picture of why a woman may be struggling to conceive.
The follicles that produce AMH are the antral and pre-antral follicles. Antral follicles are the most mature ovarian follicles, while pre-antral follicles are at the preceding stage of maturity. AMH production from these growing follicles stops small follicles that are immature (at the primordial follicle stage) from being recruited into the maturation process. This prevents all of the oocytes from maturing at the same time so that a woman releases just one mature egg in each menstrual cycle. In women, AMH is expressed by the granulosa cells in the ovaries.
Because the level of AMH shows the number of eggs maturing in the ovaries and on their way to ovulation, it is a strong indicator of a woman's ovarian reserve (OR). This is the egg supply, or the ovaries' ability to produce good-quality eggs. In fact, AMH testing is an even better method of ovarian reserve testing than antral follicle count.
Sometimes, AMH is also referred to as Mullerian inhibiting hormone (MIH), Mullerian inhibiting factor (MIF), or Mullerian inhibiting substance. This title comes from male developmental biology. Men also produce the AMH hormone, which is expressed in the Sertoli cells of the testicles. During the fetal stage, AMH causes the Mullerian duct to regress in males, which leads to the development of male sex organs. In females, the Mullerian duct becomes the reproductive tract. In adult life, AMH affects fertility for both men and women.
Declining AMH Signals Declining Ovarian Reserve
As women age, the number of follicles/eggs available for reproduction gradually declines. Together with the follicles, anti-Mullerian hormone levels also decline with age. In reproductive endocrinology, we can assess ovarian function (how well a woman’s ovaries are functioning) by evaluating her AMH levels. Women with low levels have low ovarian function and reserve, a condition called diminished ovarian reserve (DOR), or as we call it at CHR, low functional ovarian reserve (LFOR).
When serum anti-Mullerian hormone levels on the AMH blood test are low, patients will commonly have lower pregnancy chances (with or without in vitro fertilization) compared to women of the same age with normal levels. In these cases, fertility treatment must be carefully tailored to each patient’s ovarian reserve status (as well as other compounding factors) in order to achieve success. This individualization of IVF protocols is what differentiates CHR from most other IVF centers.
AMH Test Results
When patients receive their test results, they are often left with many questions. What affects AMH levels? Does low anti-Mullerian hormone mean poor egg quality? Does it mean infertility?
Low amounts of AMH indicate that there are few very immature follicles, or eggs, developing in the ovaries weeks to months before ovulation. When there are few eggs that are coming into the maturation process, obviously fewer eggs will mature eventually. Thus, low anti-Mullerian hormone is an indicator of low ovarian reserve, meaning that the patient is producing few eggs that can be used for fertilization later on.
When trying to conceive naturally or with fertility treatments like in vitro fertilization, a woman with low anti-Mullerian hormone levels will have lower chances of conceiving. In addition, AMH test results that come back low usually indicate poor egg quality. This is because egg quantity and egg quality typically go hand in hand. In combination with other tests and clinical history, your IVF specialist will be able to best advise you on how your AMH levels affect your own personal fertility chances -- and what can be done about it.
How is FSH used with AMH to Assess Ovarian Function?
Follicle stimulating hormone (FSH) is a gonadotropin that is measured to assess ovarian function alongside AMH. FSH levels are also measured using a blood test. But because FSH serum levels change throughout the menstrual cycle, the FSH test is typically performed specifically on day 2 or 3. Meanwhile, serum AMH levels can be measured at any time during the menstrual cycle. Conversely with AMH values, FSH levels increase with age. At some fertility centers, inhibin B is used as an additional marker of ovarian reserve. Like AMH, inhibin B declines with age.
How is AMH Related to Polycystic Ovarian Syndrome?
Polycystic ovarian syndrome (also called polycystic ovary syndrome, or PCOS), is also related to follicle maturation in the ovaries. With PCOS, follicles stop their maturation process in the preantral stage, and that is why at least one form of PCOS is characterized by anovulation (a woman does not ovulate, because the follicles don’t mature), amenorrhea (no periods), and hyperandrogenism (high testosterone levels). Women with polycystic ovary syndrome actually tend to have high AMH, due to many immature follicles trapped in the ovaries.
What Can Cause AMH to Be Low?
AMH levels naturally decline with age, as the supply of eggs a woman was born with begins to run low toward menopause. This can be happening at the appropriate time or prematurely, as in premature ovarian failure. Aside from normal age-related decline, almost anything that disrupts the feedback cycle of follicular development and AMH secretion can cause anti-Mullerian hormone levels to be low, like an autoimmune attack on the ovaries or genetic factors. One of the more recent research findings at CHR found that women with a particular type of the FMR1 gene were more likely to develop DOR at a younger age.
Women with anti-Mullerian hormone that is low may experience a higher incidence of miscarriage, and may even experience recurrent miscarriages, due to the poor egg quality. In this case, seeking the appropriate treatment proactively, before getting pregnant, can help prevent further pregnancy losses.
Tailored Treatments at CHR
CHR physicians develop tailored treatment approaches in order to maximize pregnancy chances with IVF for women with low--and sometimes so low that they’re undetectable--levels of AMH. Partly because we assess each woman’s fertility using age-specific reference charts for FSH and AMH measurements, we are able to determine and treat the precise cause of her infertility. We have decades of experience treating cases of anti-Mullerian hormone infertility through a variety of methods including a combination of DHEA supplementation and specialized IVF protocols with ovarian stimulation appropriate for each woman’s ovarian reserve. In the last decade, CHR’s reproductive medicine research focus has been on low ovarian reserve, so our nuanced treatments are based on in-house research, with many only available at CHR.
The Center for Human Reproduction is always at the forefront of the latest anti-Mullerian hormone research. Stay up to date with the most recent findings by reading CHR’s fertility updates. If you have additional questions about anti-Mullerian hormone, or would like to schedule a consultation to discuss your fertility test results and your way forward, feel free to contact us today.
Read more about Anti-Müllerian Hormone
Anti-Müllerian Hormone (AMH) is a hormone secreted by the cells of the developing...
Norbert Gleicher, MD, leads CHR’s clinical and research efforts as Medical Director and Chief Scientist. A world-renowned specialist in reproductive endocrinology, Dr. Gleicher has published hundreds of peer-reviewed papers and lectured globally while keeping an active clinical career focused on ovarian aging, immunological issues and other difficult cases of infertility.
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