What can AMH tell you about your fertility?

Wouldn't it be great if there were a crystal ball that could tell us how much time we have left to start a family and how easy we'll find it to get pregnant? 

Unfortunately, even with modern science, there is no crystal ball. But, with the right tests, it is possible to get some indications around the possibilities of conception.  

First, we need to consider what factors could influence the chances of conceiving.  

Factors that affect the chances of conception include: 

• The quality of eggs 
• Whether or not you’re ovulating  
• If something is stopping your partner’s sperm from reaching your eggs (such as scar tissue)  
• The quality and quantity of your partner’s sperm 

One of the other important factors that influences fertility is the total number of eggs you have – this is called your ovarian reserve [1].  

What is your ovarian reserve? 

Ovarian reserve is a term that is used to describe the reproductive potential left within a woman’s two ovaries, based on the number and quality of her eggs.  

All women are born with all the eggs they will ever have – this is usually between one and two million eggs. As you grow (even before your period starts), you lose thousands of eggs a year. On average, by the time you reach puberty, you will have around 400,000 eggs remaining [2]. 

This steady depletion will continue until menopause, where you will have no viable eggs left. This is why finding out information on your ovarian reserve could be a helpful insight into future conception.  

If you knew that you had fewer eggs than the average woman your age, would you bring your timeline of having children forward? This is where modern science does come in. You can test your ovarian reserve with a simple blood test that measures your AMH levels.  

How do you measure ovarian reserve? 

Anti-Müllerian hormone (AMH) levels can be tested as part of investigating ovarian reserve.  

AMH is a hormone produced by the follicles (tiny egg-containing sacs) growing in your ovaries [3]. When you ovulate, your ovary releases one of these eggs into the fallopian tube for fertilisation.  

AMH correlates strongly with the number of follicles (and therefore eggs) you have – and as we know, these follicles decline with age.  

If a blood test shows that you have a lower AMH level than the average person your age, it may indicate that you have fewer eggs left and could reach menopause earlier than average. 

Can AMH tell me when to start a family? 

First, it is important to say that a lower-than-average AMH level for your age won't tell you much about your chances of getting pregnant – it only takes one healthy egg and one healthy sperm for conception to occur. Have a look at our blog on age and fertility to understand the odds of pregnancy throughout your lifetime.  

And even if your AMH level is lower than other women your age, that doesn't mean that you won't still produce one healthy egg. The key is whether the egg is genetically normal, which is influenced much more by your age than your ovarian reserve.  

What an AMH Blood Test might tell you though, is whether you may reach menopause earlier than average i.e. when you may have little to no eggs left.  

The average woman reaches menopause (defined as having had no periods for a year) at age 51 [4]. However, in the ten years preceding menopause, the quality and quantity of eggs produced, declines rapidly.  

If an AMH test suggests you might reach menopause earlier than average – then you might decide to bring your timeline for having children forward. And if you aren't in a long-term relationship or not ready to start a family, you may choose to freeze some of your eggs.  

How is AMH used in fertility treatments? 

If you are starting fertility treatment or have decided to freeze some of your eggs, an AMH Blood Test can help your fertility doctor estimate how many eggs might be retrieved in a cycle. Your fertility doctor may use drugs to stimulate your ovaries to produce more eggs than in a normal cycle. These are then harvested to be frozen or fertilised in vitro.  

Before starting IVF treatment or egg freezing, your doctor is likely to use your AMH level to help estimate the dose of drugs that are given to stimulate egg release. A low AMH level may require higher doses to achieve the same response.  

Having very low levels of AMH may mean your chances of successful IVF are lower, but is still possible, even with undetectable levels, so this should not be a sole reason to exclude IVF.  

AMH tests for fertility treatment need careful interpretation by your fertility doctor, who will also consider other factors, like your age. 

What does a normal or high AMH level tell me? 

A normal AMH level means you have a similar number of eggs to other women your age. However, this doesn’t necessarily tell us that you have all the time in the world to start a family, or that you will definitely be able to. There are still other factors that can affect your fertility and AMH doesn’t tell us anything about the quality of eggs.  

You can read more information about infertility, factors that can influence it, and ways to increase your chances of conception, in our fertility guide. 

A high level of AMH may give reassurance that you have plenty of eggs, but in some cases, it could indicate a condition called polycystic ovary syndrome (PCOS) [5].  

This is a common condition where your ovaries produce high numbers of follicles every month. These follicles can take a long time to develop into a viable egg leading to irregular periods and making it more difficult to predict ovulation and get pregnant.  

As AMH correlates with follicle numbers, the likelihood of PCOS increases as AMH increases. If your AMH level is higher than expected, it would be worth following up with a Polycystic Ovary Syndrome Blood Test to check whether polycystic ovaries could be the reason, especially if you have any symptoms of PCOS. 

You can read more about PCOS and fertility in our blog: how can PCOS affect fertility?.

So, what can AMH tell you about your fertility?  

An AMH test isn't quite the crystal ball we'd like it to be. It can't predict whether you have healthy eggs, and it can't identify whether a physical problem might affect you or your partner.  

But, what it can do is help you understand your fertility timeline. An AMH test can tell you whether your levels are normal or not for your age. If an AMH test is higher than expected, you may want to investigate PCOS. And if an AMH test shows that your levels are lower than average for your age, then you might want to bring your timeline for having children forward - just knowing can help you to make informed choices.  

If you want to find out more information on infertility, what treatments can help you to conceive, and where to get support, see our fertility guide, or our blog on age and fertility. 

References 

1. nhs.uk. 2022. IVF. [online] Available at: <https://www.nhs.uk/conditions/ivf/getting-started/#:~:text=All%20IVF%20clinics%20in%20the,will%20respond%20to%20IVF%20treatment.> [Accessed 14 July 2022]. 
2. Silber, S., 2015. Unifying theory of adult resting follicle recruitment and fetal oocyte arrest. Reproductive BioMedicine Online, 31(4), pp.472-475.  
3. Uhcw.nhs.uk. 2022. [online] Available at: <https://www.uhcw.nhs.uk/clientfiles/files/IVF/CRM%20AMH%20Patient%20Information%20(GEN-PI-000213V11).pdf> [Accessed 14 July 2022]. 
4. Nhsinform.scot. 2022. Menopause. [online] Available at: <https://www.nhsinform.scot/healthy-living/womens-health/later-years-around-50-years-and-over/menopause-and-post-menopause-health/menopause#:~:text=In%20the%20UK%2C%20the%20average,seeking%20support%20from%20healthcare%20professionals.> [Accessed 14 July 2022]. 
5. Tal, R., Seifer, C., Khanimov, M., Seifer, D. and Tal, O., 2020. High serum Antimullerian hormone levels are associated with lower live birth rates in women with polycystic ovarian syndrome undergoing assisted reproductive technology. Reproductive Biology and Endocrinology, 18(1).