What is AMH?
- AMH, or anti-mullerian hormone is a substance produced by granulosa cells in ovarian follicles.
- It is first made in primary follicles that advance from the primordial follicle stage. At these stages follicles are microscopic and cannot be seen by ultrasound.
- AMH production is highest in preantral and small antral stages (less than 4mm diameter) of development.
- Production decreases and then stops as follicles grow. There is almost no AMH made in follicles over 8mm.
- Therefore, the levels are fairly constant and AMH testing can be done on any day of the woman’s cycle.
How can AMH hormone levels be a fertility test?
Since AMH is produced only in small ovarian follicles, blood levels of this substance have been used to attempt to measure the size of the pool of growing follicles in women.
- Research shows that the size of the pool of growing follicles is heavily influenced by the size of the pool of remaining primordial follicles (microscopic follicles in “deep sleep”).
- Therefore, AMH blood levels are thought to reflect the size of the remaining egg supply – or “ovarian reserve.”
With increasing female age, the size of their pool of remaining microscopic follicles decreases. Likewise, their blood AMH levels and the number of ovarian antral follicles visible on ultrasound also decrease. To learn more about age and fertility, read Dr. Marcy Maguire’s blog: What Is a Woman’s Age for Peak Fertility and When Does Fertility Begin to Diminish?
Women with many small follicles, such as those with polycystic ovaries (PCOS) have high AMH hormone values and women that have few remaining follicles and those that are close to menopause have low anti-mullerian hormone levels.
AMH levels and pregnancy chances with in vitro fertilization
Women with higher AMH values will tend to have better response to ovarian stimulation for IVF (in vitro fertilization), with more eggs retrieved. It has been documented that women with lower AMH have lower antral follicular counts and produce a lower number of oocytes (eggs).
AMH levels probably do not reflect egg quality. Having more eggs at the IVF egg retrieval provides an opportunity for a greater number of eggs to fertilize and develop into embryos. More eggs does not always mean more embryos. Egg quality plays a role in the fertilization and development of embryos. The ultimate goal is to have at least one healthy embryo to transfer back into the uterus.
What are normal AMH levels?
Interpretation of anti-mullerian hormone levels
There are some inconsistencies to consider when interpreting AMH hormone levels. Since the AMH test has not been in routine use for many years, the levels considered to be “normal” are not yet clarified and agreed on by the experts. Also, not all current commercial assays give equivalent results.
The table below has AMH interpretation guidelines from fertility literature. It is important not to be caught up by the cutoff values shown below.
For example, the difference between 0.6 and a 0.7 ng/ml test result puts a woman in a “different box” in this table- but there is very little real difference in fertility potential. In reality, it is a continuum – and not something that categorizes well.
AMH Blood Level
|High (often an indicator of PCOS)||Over 3.0 ng/ml|
|Normal||Over 1.0 ng/ml|
|Low Normal Range||0.7 – 0.9 ng/ml|
|Low||0.3 – 0.6 ng/ml|
|Very Low||Less than 0.3 ng/ml|
The below graph shows the average AMH level for women not experiencing trouble conceiving, according to age.
PLEASE NOTE: the above table, AMH Blood Levels (by ng/ml) should not be compared to the graph below (measured by pmol/l) as they are measured in different increments.
More will be learned regarding anti-mullerian hormone levels and outcomes as we continue to use the AMH fertility test and study the relationship between AMH hormone values, fertility and ovarian responsiveness.
Ovarian reserve testing methods
Anti-mullerian hormone is one potential test of ovarian reserve. There are other tests that are currently used for evaluation of the remaining egg supply. Fertility specialists often use a combination of fertility tests to best assess a woman’s ovarian reserve, including a transvaginal ultrasound to count the number of antral follicles and other hormone levels.
HOW DO FSH AND AMH LEVELS AFFECT PREGNANCY?
Dr. Marcy Maguire, lead physician at RMANJ’s West Orange office, recently explained FSH and AMH in detaile on an episode of This is Infertility, a new podcast examining what it’s like to be infertile in the U.S.
You can listen to the entire episode in the audio player below or read Dr. Maguire’s discussion below.
What is premature ovarian aging, premature ovarian insufficiency or diminished ovarian reserve?
Dr. Maguire: All of the above mean essentially the same thing: the ovaries have less eggs in them than they should, given the woman’s age. Diminished ovarian reserve is not synonymous with whole body aging – it doesn’t mean that the woman herself is somehow aging prematurely, it just means her egg count overall is lower than it should be given her age.
What are the symptoms of premature ovarian aging?
Dr. Maguire: The two most common symptoms are infertility and irregular or skipped menstrual cycles.
How can premature ovarian aging be diagnosed?
Dr. Maguire: The best diagnosis will come from FSH and AMH levels, and then an ultrasound – all three can be markers of a lower egg count.
What is FSH?
Dr. Maguire: FSH, or follicle-stimulating hormone, is a hormone produced by the pituitary, an organ in the brain that encourages follicles and eggs to grow and mature each month. If the FSH level starts to go up, typically above the number of ten, that means that the brain is trying hard to stimulate the ovaries to produce eggs but having a hard time getting the ovaries to listen. So the FSH goes up and up, getting louder and louder and louder, trying to get the ovaries to listen – but there just aren’t many eggs left, so the ovaries are having a harder time producing.
What is AMH?
Dr. Maguire: AMH, or Anti-Mullerian hormone, is a hormone that is made by granulosa cells that take care of the eggs, so the more eggs a woman has, the more granulosa cells she has, and the higher her AMH. We like to use AMH as a marker of a woman’s overall egg count. If the AMH is above 1.2, we feel relatively reassured, and if it’s less than 1.2, that is more concerning. Of course this will also correlate with a woman’s age, so a woman in her early 30s with a low AMH less than 1.2 is very worrisome, whereas it’s more common for women in their early 40s to have a low AMH.
How do you test for FSH and AMH?
Dr. Maguire: A blood test will identify a woman’s FSH and AMH levels.
What are fertility options for women with high FSH and low AMH?
Dr. Maguire: If a woman has diminished ovarian reserve, meaning an overall lower egg count, she still may have the opportunity to have children using her own eggs – it just depends on her relative level of eggs. If there are some there that we can access, typically we would do in vitro fertilization (IVF) to get to them and potentially even bank some so that the woman could use them in the future when her egg count would be expected to be even lower.
What if a woman cannot use her own eggs at all?
Dr. Maguire: When a woman’s egg reserve is so low that she is in the early stages of menopause, fertility treatments typically can’t help a woman use her own eggs – but donor eggs are available and the woman can carry the pregnancy herself. This can be done with a known or anonymous egg donor.
For women considering using an egg donor, it’s important to make peace with that decision — to take time to process it, talk with counselors to consider all implications and then go forward. For all the patients I’ve had, once they get over that hump and say ‘yes, this is an option for me,’ they are very happy with the decision.