AMH (Anti-Mullerian Hormone)

Hello to all. In this blog I will review the usefulness of Anti-Mullerian Hormone, otherwise referred to as AMH.  AMH is one of the hormones, along with estrogen and a few others, produced by the ovary.

Like estrogen, AMH is produced by the granulosa cells. The granulosa cells are the small cells that surround each egg.  These small cells are tightly attached to egg surface whereby they help to vitalize and, when the time is right, mature the egg.   This egg-granulosa cell unit is called the follicle.

No one yet knows what the function of ovarian AMH in females.  AMH is present in males, and we know that it has a very important role in the development of normal male sexual anatomy.  What we do know about AMH in females is that the more healthy follicles one has, the higher the AMH levels.

Measurement of AMH levels can help us predict a woman’s fertility, in a very general way.  We already said that estrogen is also produced by the granulosa cells, so why wouldn’t we just need to measure estrogen levels to find out about ovarian health?  Because estrogen only comes from follicle at a time; the one that is in the process of ovulation. A woman may have 100,000 follicles, but on most cases only one per month gets involved in ovulation and becomes an estrogen producer.   Follicles may make different amount of estrogen each month, so judging fertility based on an estrogen test is not helpful.

Many follicles at one time, however, are producing AMH. Now it’s not every follicle, but it is a large number.  It works like this. The ovary contains different follicles in different stages of maturity.  Here is a microscopic view of the ovary.

 

Some follicles are very immature and have few granulosa cells; just one layer surrounding the egg.   Some follicles are more mature and their granulosa cells have multiplied into more cells in multiple layers.  These are the ones producing the most AMH.  In general, if you have a lot of eggs, you have plenty of follicles in all of the stages of development, giving you higher AMH levels.  Lower AMH levels mean fewer follicles of all types.

Follicles are always making AMH therefore levels can be measured any day in the cycle. In fact, it does not matter if a woman is on oral contraceptives, AMH is still produced and can be measured.

AMH may turn out to be and excellent way to measure a woman’s fertility potential, but we are not quite there yet. We do know that a high AMH is good and a low AMH is bad. What’s a good high level? We are still not sure. We know a little.  Any level over 2 is really not bad at all. Certainly, higher than 2 is better still. We know that undetectable levels, less than 0.16, are bad.  But, we have had women with these low levels become pregnant.  The odds of pregnancy are much worse for women with low levels, but people frequently get pregnant with low odds.  Some women have asked me if the level can be too high.  High levels may indicate the presence of polycystic ovaries (ovaries with an above average number of follicles).  While it is true that some women with polycystic ovaries have trouble conceiving, a high AMH level is not the issue.

Recent studies (one was in the headlines a few weeks ago) have used AMH levels to predict IVF outcome.  But again, really high levels were shown to be good and really low levels bad, but overall, not predictive enough to tell someone they can or can not get pregnant.

What we typically do is to put all of the information we have together to estimate ovarian health.  If we use age, FSH levels, AMH, antral follicle counts, the prognosis becomes a bit more clear, but the system is still not perfect.

AMH testing will become more useful sometime soon. More and more women need to have the test done do we can compare levels to outcomes on a large scale. In addition the laboratories need to get better at the testing.  But once we get better with AMH levels, we may be able to do some very important things.

For instance, some studies have been done comparing AMH levels to the time of menopause. Again, not ready for prime time, but the concept may be very important.  What if we could measure AMH in a young woman and determine at what age she will start losing her fertility? Or at what age will she lose half her fertility? What if we could measure AMH levels in a woman destined for chemotherapy and determine if she should freeze her eggs first?

These would all be wonderful uses of this test and it may be that in the future we could reach these goals.

It’s more likely that newer tests will be developed to improve ability to predict.  As alluded to before, combination tests may be more accurate. For example labs are starting to market “fertility profiles” based on AMH, FSH, inhibin and other hormones.

But in the end, like in all of medicine, the genetic tests will dominate.  Scientists are looking for a gene or groups of genes that control the fertile lifespan of women.  As genetic testing becomes less expensive and as we increase our ability to look at more and more genes at one time, the goal of accurately determining a woman’s ovarian age and potential will be reached.

 

Thanks for reading and please don’t forget to read the disclaimer from 5.17.06

 

Dr. Licciardi

 

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