Is the AMH Test Reliable?
Dr Fleur Cattrall | 6th Dec 2013
Recent media coverage has drawn considerable attention to the anti-Mullerian hormone or AMH test. The discussion was around whether this ‘egg timer test’ was worth doing or whether its time had run out.
What is AMH?
Anti-Mullerian hormone, also known as AMH, can be measured by a blood test. AMH is released from the total pool of eggs left in ones ovaries. A woman is born with all the eggs she will ever have. These eggs decline in numbers with age and so does the AMH level. The level of a woman’s AMH level can be compared with the range expected for her age.
There is only a slight variation in the hormone level when tested in different parts of the menstrual cycle so the test can be performed at any time.
The levels are reasonably reliable for most women whilst on the oral contraceptive pill which can sometimes artificially lower the level of AMH. There has been reported variation in results from different pathology departments and this has been one of the reasons for recent criticisms of the test.
But on the whole it remains a useful test when performed by an experienced laboratory but needs to be interpreted in context of the clinical situation.
What the AMH test can’t do
The recent article has raised some debate regarding who should be having this test.
It is a dilemma that women who have not even attempted trying to conceive are requesting this test. A test result that is not in the normal range for her age undoubtedly causes panic. Much of this panic will be unnecessary.
The real problem with both AMH and any other test for ovarian reserve for that matter is that there is no way to assess egg quality. There will be many women that had very low AM
H levels but conceived in their first month of trying.
For the unsuspecting woman that has not even tried to conceive and discovers an alarmingly low result, there may be a benefit. It is to highlight the importance of making plans to have a baby.
One of the risks of finding a normal result however, is that a woman may be falsely reassured that her fertility is ok and delay a family for longer. Even a woman in their mid-40s can have a high result sometimes. But those eggs have been around for a long time, exposed to the same ageing process that affects the rest of our bodies. Therefore it gets harder to get pregnant and stay pregnant as a women gets older.
How can AMH Results be Helpful?
An AMH level can be a useful tool for a fertility specialist planning treatment. It can guide clinicians on the dose and regimen of treatment, as well as give an indication of the likely egg number range a woman might achieve with IVF. However, ultrasound might be just as good for this purpose. A doctor might predict a high or low egg number with IVF based on these tests.
This is not a perfect science as each month is different and each woman’s response to treatment can vary. The number of eggs obtained is not the main focus, it’s the quality that counts. There is no good test for egg quality.
The test result should be part of an overall assessment of a woman’s chances of conceiving. An ultrasound is a very useful test to do. The ovarian reserve, or total number of eggs, can be inferred by the number of baseline follicles seen on ultrasound. The ultrasound adds support to the results of the AMH level in most cases.
We really need to talk about these results in the context of all the other fertility factors for an individual. Included in this are their plans for the future:
- Have they been trying to conceive?
- For how long?
- Are they planning more than one child?
- Have they got a partner?
- Should we be considering egg freezing?
- Is there a family history of early menopause?
- Should they bring forward their plans to have a baby?
The main message needs to be that an AMH is one of many bits of information that builds a picture. It is not a test for egg quality, only quantity. It should be performed by someone who is knowledgeable on the pros and cons of the test so that when that result arrives, it can immediately be put into context for you.
We cannot predict reliably when your eggs will run out. Female age is a better predictor of egg quality than AMH. A low result does not mean your fertile days are over. Just ask all the women out there that had low ovarian reserve and are now holding their babies.
The clock is ticking but an AMH will not tell you when your time is up.