What is AMH ?

AMH stands for Anti-Mullerian Hormone. It is also called MIS ( Mullerian Inhibiting Substance) . Since AMH is produced directly by the ovarian follicles, AMH levels correlate with the number of antral follicles in the ovaries . It has been documented that women with lower AMH  have lower antral follicular counts and produce a lower number of oocytes compared with women with higher levels.

 AMH Reference ranges

 AMH levels do not vary with the menstrual cycle and  can be measured independently of the day of the menstrual cycle.

AMH can be used for

 1.       Evaluating Fertility Potential and ovarian response in IVF – Serum AMH levels correlate with the number of early antral follicles. This makes is useful for prediciting your ovarian response in an IVF cycle. Women with low AMH levels are more likely to be poor ovarian responders.

2.       Measuring Ovarian Aging – Diminished ovarian reserve, is signaled by reduced baseline serum AMH concentrations. Women with poor ovarian reserve who have entered the oopause have low levels of AMH. However, this is a new test, and is still not easily available.

AMH versus FSH

The old standard for ovarian reserve testing was the Day 3 FSH level.

However, the FSH level is not as reliable as the AMH level for 3 reasons.

1. The FSH level varies according to the cycle dates

2. It depends upon the estradiol level ( a high estradiol level will artificially suppress a high abnormal FSH level into the normal range)

3. It varies from cycle to cycle, so is not always reliable or dependable

An AMH level is a much better marker for  ovarian reserve. It is much more stable than the FSH level and does not vary from cycle to cycle. Even better, it can be measured on any day of the cycle ! This is why most infertility specialists today use AMH to check ovarian reserve, rather than the old FSH level.

One confusing thing about AMH is that there are at least 2 scales out there and innumerable clinic definitions of what is "normal" - it depends on which assay they use and which study!  One scale is ng/ml and one is pmol/l.  The pmol/l scale runs from 0 to about 48; the ng/ml runs from about 0-10.  On the ng/ml scale , less than 2 ng/ml is considered to be low. 

An AMH level can also be very useful for young women who want to postpone childbearing and want to check their fertility. Many women these days are postponing having a baby in order to pursue a career. The good news is that while usually fertility does not decline too much until the age of 32, for some women the decision to postpone childbearing can prove to be one they bitterly regret later on. Fertility does decline as a woman grows older, and the problem is that it is not possible to predict the rate of decline for an individual woman. Most women are lulled into a false sense of security if they have regular period, because they assume that if their periods are regular, this automatically means that their egg quality if enough for them to make babies !

Unfortunately, this is not always true - and for some women, while their egg quality is enough for them to produce enough hormones to get regular periods, it may not be enough to make a baby !

Suppose you are 32 and want to postpone childbearing for another year because you have a very good chance of getting a promotion ? Is it safe to do so ? Or will this be something you will kick yourself for later on when your IVF doctor says - I wish you had come to me earlier ? I'd suggest you get your AMH level tested. If you live in the US, you can get it done at www.mymedlab.com.

If it's low, you might want to re-think your priorities. If it's normal, then it's fine to postpone childbearing, but do get the test repeated every year. If it starts dropping, this is a sign you might want to pay attention to your biological clock before it is too late !

Please do remember that doctors do not treat numbers - we treat patients, so don't obsess over just one number is isolation.

The final proof of the pudding is in the eating - and your response to superovulation is the best way of assessing your ovarian reserve. If you grow eggs well, then you should not worry about your "numbers" !