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Conception Aug 28, 2019
8 Minutes

Ask the expert: AMH: The number you REALLY need to know when it comes to fertility….

This article and podcast is with one of our resident expert advisors discussing all you need to know about AMH. A key hormone which can tell you a lot about your fertility. We discuss what it is, how it works and why Mr Karoshi thinks every girl should know her number.

Podcast alert: to listen – click here. – for the highlights – read on:

The reality is, on average, as a generation, we are older than our parents when it comes to having children. There are pros and cons to this of course; being older brings maturity and greater chance of being more settled emotionally and financially to name just two – the unfortunate downside here (whether we like it or not) age is not kind to our fertility…

However, knowledge as always is empowering, and being knowledgable around our own bodies is only ever a good thing – particularly when it comes to making educated choices and decisions around ‘the right time’ for a baby given our new modern lifestyles.

This is where knowing your AMH level can be so powerful.

We sat down with one of our expert advisors Mahantesh Karoshi aka @gynecologist_london to discuss all you need to know about this level. Why it is so important, how to measure it, what ‘the best level’ is, what affects it and how you can support it. Click here for the full podcast interview or carry on reading below for the need to know:

So – what exactly is AMH?

This is short for Anti Mullerian Hormone – a Hormone that is produced by the ovaries. This is a reflection of ovarian function and reserve. It was discovered around 20 years ago and is most commonly used now as a prognostic tool or indicator of fertility potential for women.

What is Ovarian Reserve?

As females, when we are born, we are born with a finite supply of eggs or ‘follicles’. Ovarian reserve is the amount of follicles (eggs) remaining in a woman’s ovaries. AMH cannot give an exact picture of the number we have ‘left’ (which does decline with age) but it can give an indication. For a better picture we really need to see how the AMH level moves over time.

How does this hormone give us a picture of our ovarian reserve?

Firstly it is the ovaries which produce AMH. In every woman there are tiny follicles that are arrested at a certain level of development. Once a woman starts menstruating, each month about 10-15 follicles get recruited and start to further develop. Within that number, one becomes dominant and that continues through to ovulation. If a woman is running low the 10-15 eggs that should be recruited will be low – and a woman with low reserve wont recruit the average of 10-15 eggs. AMH is actually produced once these eggs have been recruited and stimulated so a low number indicates that a lower number than the ‘ideal’ 10-15 eggs.

What causes AMH levels to change?

There are a variety of factors but the principal ones are age, stress and social/lifestyle factors. When it comes to stress and lifestyle factors three of the worst are smoking, alcohol and obesity.

Age is clearly a major factor, is it a linear decline as we get older?

Actually no. Between the ages of around 14-22yrs old AMH rises. It then tends to stabilise until 30-31yrs old where the decline typically then starts. It is then a case of watching the rate of decline.

What are some of the variables that can accelerate the decline?

Genetics and lifestyle are the major factors. As above, smoking, drinking and being overweight will lead to an accelerated decline when it comes to AMH – however if you’re living well, genetics can cause a fall off – the biggest signal of risk of this is if your mother/sister had early menopause (defined as menopause starting from 35 yrs old).

How does lifestyle actually work causing AMH to drop?

It is all to do with blood flow to the ovaries. Anything that reduces blood flow will affect the growth potential and development of follicles. Smoking is the one that has the worst impact due to the decline in oxygenation in the blood. At a cellular level and from the perspective of egg quality oxidative stress is the other factor that causes a decline in egg count and quality – click here for more on that.

Speaking of egg quality – is AMH any indication of quality?

Yes – low AMH levels typically correlates to low quality. An egg of lower quality gives off less AMH hormone. That being said normal AMH doesnt necessarily mean good quality – although it does suggest lower risk of poor quality eggs.

How often should we be testing AMH?

There are no internationally set official standards, however most specialists tend to agree that an ideal approach is starting from 18yrs old to establish your ‘baseline’ level and then test every 5yrs until the age of 25. Then once/year following that to assess the rate of decline. When it comes to premature menopause and in particular if your mother/relation has suffered from early menopause it is more important to get tested early and more regularly to monitor this.

What causes early menopause?

This is usually a chromosomal abnormality and hence it is often passed down from the previous generation.

How do we test AMH level?

Its actually a very simple blood test – you can even order the test online if you would prefer not to go to your doctor. It just takes 15 drops of blood and can be done anytime during your menstural cycle.

So you’ve done the test: what is an ‘ideal’ level?

Big picture a level of 15 and above is the ideal. Less than 5 is very concerning but that does not mean that there is no hope of conception. An ‘ideal level’ is also somewhat age dependent. A level of 15 would be concerning in a 21yr old but not a concern in a 35yr old. For someone in their early 30s: 15 and above is good. If you have a level of between 5-15 you need careful monitoring to assess how rapidly this is dropping. When it comes to egg freezing many clinics (not all) wont take a level of below 15 so that is another reason why regular testing and being aware is crucial.

(Important note: AMH pertains to its levels pmoL/L in the UK vs the US and Europe who use nmol/L: the conversion factor is 7.14 which means that in the UK if your AMH is 7.14 for Europeans and Americans that is 1).

Why is AMH important for egg freezing?

This comes down to egg quality and viability. Low AMH typically correlates to lower quality and less chance of viable eggs for freezing. That’s why a lot of clinics want to see an AMH of 15-20 largely because you want to attain ideally 20 viable eggs. An AMH lower than 15/20 suggests that it could take longer than 2/3 cycles to attain that level and therefore not seen as realistic. Another reason why knowing your number is crucial.

How quickly do these levels tend to drop?

This is very hard to predict and varies from person to person – this is why you need regular testing. Another good indicator of chances of a rapid drop in AMH is additional testing of FSH and LH levels. A level of above 10 for these hormones could indicate a chance of a more rapid drop coming. The reason being that as the ovaries age the brain sends more signals to get increased recruitment of eggs, the ovaries also become increasingly resistant to the hormones so the levels rise.

What factors can cause a very different level of AMH to the normal range?

There are several factors or conditions that can cause an unusual level. Chemotherapy is one and has a direct impact on follicles as do functional ovarian tumours (which can cause an AMH reading in the thousands). A more common condition that impacts AMH is Polycystic Ovarian Syndrome (PCOS) which actually impacts 30% of women – some of which have no idea that have the condition. Typically it causes a level of 40+.

Why does PCOS cause a higher AMH number?

When a person has PCOS this causes the follicles within the ovaries to stop growing mid stage within the ovaries and this causes high levels of AMH to be released. The other issue is that these follicles do not always get released as PCOS can cause issues with ovulation. This is why additional testing (FSH/LH levels and ultrasound scan) is a good idea. It is more difficult to assess ovarian reserve for a PCOS patient therefore and keeping a close eye on the rate of change is also more important.

What are some of the limitations of the test?

It is a pretty reliable test on the whole and the good news is that you can test anytime during your cycle (unlike FSH and LH levels which need to be tested on particular days). That being said – it is a hormone and therefore there is fluctuation, another reason we need testing more than once.

What happens if you have a low AMH (ie. below 5):

When it comes to arresting the decline or increasing the number, currently there isnt anything in the UK that will increase it. So it is all about stalling the fall. There are a few things that you can consider – available without prescription. One is DHEA. This works by entering the follicles and where follicular arrest has happened it will actively stimulate it. So, the follicles won’t be new but there will be follicles that are ‘stuck’ and this can help unlock the development and the blocked cascade. The only thing here is that professional advice is needed before you start to take this as a supplement as you need to know the correct dose and to have careful monitoring for response – no drug has zero side effects.

The other is CoQ10/Ubiquinol. This targets the oxidative stress – so can potentially be effective if you have had a lifestyle which may have contributed to damage. Click here to learn more.

What about new technologies around egg reserve, quality and AMH?

One of the emerging technologies is known as PRP which stands for Platlet Rich Plasma which harbours stem cells. Everyone has them in their blood in small amount. This blood is then collected and centrifuged to extract the stem cells themselves and they are then activated by adding calcium and if you inject this anywhere this starts to stimulate growth of new blood vessels and nerves – they revitalise older tissue. This has been tested in Serbia – is not available in the UK currently. This practise is being done where this is injected back into the Ovaries and the Ovaries are producing eggs and successful pregnancies have been reported.

What exactly is a stem cell? How can it be so powerful?

Stem cells have the potential to become any organ you like. As a newborn, or very young person the majority of your cells are stem cells but as you age the proportion declines. The reason this treatment is not available in the UK is because stem cells are tricky to regulate. The reality is they can become any organ depending on the way they are treated so obviously there are substantial issues associated with that. As it stands in the UK they are mainly used within the lab for research purposes and not for public use.

Egg freezing is a technology that is becoming more popular: what is the right time AMH wise to freeze eggs?

Ideally a woman should look to freeze eggs in her early 30s. After 35yrs old it can become difficult for a clinic to accept a patient for freezing because of possibility of a higher number of defective eggs. An AMH of less than 10 is not likely to be accepted for egg freezing. The reason being ideally you need at least 20 good quality eggs which should be acquired over two/three cycles of stimulation at most. If you have low AMH (below 10) the chances are you would need a lot more rounds of stimulation in order to achieve this number. The trouble with that is that the procedure is not side effect free. So if you’re considering freezing your eggs it is yet another reason to stay aware of your AMH. Click here to learn much more about egg freezing.

If you’d like to hear more from Mr Karoshi check him out on Instagram @gynaecologist_london or at If you’d like to ask him a question please click on the contact us button.


This article is for informational purposes only. This article is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment and should never be relied upon for specific medical advice. The information on this website has been developed following years of personal research and from referenced and sourced medical research. Before making any changes we strongly recommend you consult a healthcare professional before you begin.

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